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Run idnits with the --verbose option for more detailed information about the items above. -------------------------------------------------------------------------------- 2 PKIX Working Group R. Housley (RSA Laboratories) 3 Internet Draft W. Ford (VeriSign) 4 W. Polk (NIST) 5 D. Solo (Citigroup) 6 expires in six months July 2001 8 Internet X.509 Public Key Infrastructure 10 Certificate and CRL Profile 12 14 Status of this Memo 16 This document is an Internet-Draft and is in full conformance with 17 all provisions of Section 10 of RFC2026. Internet-Drafts are working 18 documents of the Internet Engineering Task Force (IETF), its areas, 19 and its working groups. Note that other groups may also distribute 20 working documents as Internet-Drafts. 22 Internet-Drafts are draft documents valid for a maximum of six months 23 and may be updated, replaced, or obsoleted by other documents at any 24 time. It is inappropriate to use Internet- Drafts as reference 25 material or to cite them other than as "work in progress." 27 The list of current Internet-Drafts can be accessed at 28 http://www.ietf.org/1id-abstracts.html 30 The list of Internet-Draft Shadow Directories can be accessed at 31 http://www.ietf.org/shadow.html. 33 To view the entire list of current Internet-Drafts, please check the 34 "1id-abstracts.txt" listing contained in the Internet-Drafts Shadow 35 Directories on ftp.is.co.za (Africa), ftp.nordu.net (Northern 36 Europe), ftp.nis.garr.it (Southern Europe), munnari.oz.au (Pacific 37 Rim), ftp.ietf.org (US East Coast), or ftp.isi.edu (US West Coast). 39 Copyright (C) The Internet Society (2001). All Rights Reserved. 41 Abstract 43 This is the eighth draft of a specification based upon RFC 2459. 44 When complete, this specification will obsolete RFC 2459. 46 Please send comments on this document to the ietf-pkix@imc.org mail 47 list. 49 This memo profiles the X.509 v3 certificate and X.509 v2 CRL for use 50 in the Internet. An overview of the approach and model are provided 51 as an introduction. The X.509 v3 certificate format is described in 52 detail, with additional information regarding the format and 53 semantics of Internet name forms (e.g., IP addresses). Standard 54 certificate extensions are described and one new Internet-specific 55 extension is defined. A required set of certificate extensions is 56 specified. The X.509 v2 CRL format is described and a required 57 extension set is defined as well. An algorithm for X.509 certificate 58 path validation is described. Supplemental information is provided 59 describing the format of public keys and digital signatures in X.509 60 certificates for common Internet public key encryption algorithms 61 (i.e., RSA, DSA, and Diffie-Hellman). ASN.1 modules and examples are 62 provided in the appendices. 64 The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", 65 "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this 66 document are to be interpreted as described in RFC 2119. 68 Table of Contents 70 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 6 71 2 Requirements and Assumptions . . . . . . . . . . . . . . . . . . 7 72 2.1 Communication and Topology . . . . . . . . . . . . . . . . . . 7 73 2.2 Acceptability Criteria . . . . . . . . . . . . . . . . . . . . 8 74 2.3 User Expectations . . . . . . . . . . . . . . . . . . . . . . . 8 75 2.4 Administrator Expectations . . . . . . . . . . . . . . . . . . 8 76 3 Overview of Approach . . . . . . . . . . . . . . . . . . . . . . 8 77 3.1 X.509 Version 3 Certificate . . . . . . . . . . . . . . . . . . 10 78 3.2 Certification Paths and Trust . . . . . . . . . . . . . . . . . 11 79 3.3 Revocation . . . . . . . . . . . . . . . . . . . . . . . . . . 13 80 3.4 Operational Protocols . . . . . . . . . . . . . . . . . . . . . 14 81 3.5 Management Protocols . . . . . . . . . . . . . . . . . . . . . 14 82 4 Certificate and Certificate Extensions Profile . . . . . . . . . 15 83 4.1 Basic Certificate Fields . . . . . . . . . . . . . . . . . . . 16 84 4.1.1 Certificate Fields . . . . . . . . . . . . . . . . . . . . . 17 85 4.1.1.1 tbsCertificate . . . . . . . . . . . . . . . . . . . . . . 17 86 4.1.1.2 signatureAlgorithm . . . . . . . . . . . . . . . . . . . . 17 87 4.1.1.3 signatureValue . . . . . . . . . . . . . . . . . . . . . . 18 88 4.1.2 TBSCertificate . . . . . . . . . . . . . . . . . . . . . . . 18 89 4.1.2.1 Version . . . . . . . . . . . . . . . . . . . . . . . . . . 18 90 4.1.2.2 Serial number . . . . . . . . . . . . . . . . . . . . . . . 19 91 4.1.2.3 Signature . . . . . . . . . . . . . . . . . . . . . . . . . 19 92 4.1.2.4 Issuer . . . . . . . . . . . . . . . . . . . . . . . . . . 19 93 4.1.2.5 Validity . . . . . . . . . . . . . . . . . . . . . . . . . 23 94 4.1.2.5.1 UTCTime . . . . . . . . . . . . . . . . . . . . . . . . . 23 95 4.1.2.5.2 GeneralizedTime . . . . . . . . . . . . . . . . . . . . . 23 96 4.1.2.6 Subject . . . . . . . . . . . . . . . . . . . . . . . . . . 24 97 4.1.2.7 Subject Public Key Info . . . . . . . . . . . . . . . . . . 25 98 4.1.2.8 Unique Identifiers . . . . . . . . . . . . . . . . . . . . 25 99 4.1.2.9 Extensions . . . . . . . . . . . . . . . . . . . . . . . . . 25 100 4.2 Certificate Extensions . . . . . . . . . . . . . . . . . . . . 25 101 4.2.1 Standard Extensions . . . . . . . . . . . . . . . . . . . . . 26 102 4.2.1.1 Authority Key Identifier . . . . . . . . . . . . . . . . . 27 103 4.2.1.2 Subject Key Identifier . . . . . . . . . . . . . . . . . . 28 104 4.2.1.3 Key Usage . . . . . . . . . . . . . . . . . . . . . . . . . 29 105 4.2.1.4 Private Key Usage Period . . . . . . . . . . . . . . . . . 30 106 4.2.1.5 Certificate Policies . . . . . . . . . . . . . . . . . . . 31 107 4.2.1.6 Policy Mappings . . . . . . . . . . . . . . . . . . . . . . 33 108 4.2.1.7 Subject Alternative Name . . . . . . . . . . . . . . . . . 34 109 4.2.1.8 Issuer Alternative Name . . . . . . . . . . . . . . . . . . 37 110 4.2.1.9 Subject Directory Attributes . . . . . . . . . . . . . . . 37 111 4.2.1.10 Basic Constraints . . . . . . . . . . . . . . . . . . . . 37 112 4.2.1.11 Name Constraints . . . . . . . . . . . . . . . . . . . . . 38 113 4.2.1.12 Policy Constraints . . . . . . . . . . . . . . . . . . . . 40 114 4.2.1.13 Extended key usage field . . . . . . . . . . . . . . . . . 41 115 4.2.1.14 CRL Distribution Points . . . . . . . . . . . . . . . . . 43 116 4.2.1.15 Inhibit Any-Policy . . . . . . . . . . . . . . . . . . . . 44 117 4.2.1.16 Freshest CRL . . . . . . . . . . . . . . . . . . . . . . . 45 118 4.2.2 Internet Certificate Extensions . . . . . . . . . . . . . . . 45 119 4.2.2.1 Authority Information Access . . . . . . . . . . . . . . . 45 120 4.2.2.2 Subject Information Access . . . . . . . . . . . . . . . . 47 121 5 CRL and CRL Extensions Profile . . . . . . . . . . . . . . . . . 48 122 5.1 CRL Fields . . . . . . . . . . . . . . . . . . . . . . . . . . 49 123 5.1.1 CertificateList Fields . . . . . . . . . . . . . . . . . . . 50 124 5.1.1.1 tbsCertList . . . . . . . . . . . . . . . . . . . . . . . . 50 125 5.1.1.2 signatureAlgorithm . . . . . . . . . . . . . . . . . . . . 50 126 5.1.1.3 signatureValue . . . . . . . . . . . . . . . . . . . . . . 51 127 5.1.2 Certificate List "To Be Signed" . . . . . . . . . . . . . . . 51 128 5.1.2.1 Version . . . . . . . . . . . . . . . . . . . . . . . . . . 52 129 5.1.2.2 Signature . . . . . . . . . . . . . . . . . . . . . . . . . 52 130 5.1.2.3 Issuer Name . . . . . . . . . . . . . . . . . . . . . . . . 52 131 5.1.2.4 This Update . . . . . . . . . . . . . . . . . . . . . . . . 52 132 5.1.2.5 Next Update . . . . . . . . . . . . . . . . . . . . . . . . 52 133 5.1.2.6 Revoked Certificates . . . . . . . . . . . . . . . . . . . 53 134 5.1.2.7 Extensions . . . . . . . . . . . . . . . . . . . . . . . . 53 135 5.2 CRL Extensions . . . . . . . . . . . . . . . . . . . . . . . . 53 136 5.2.1 Authority Key Identifier . . . . . . . . . . . . . . . . . . 54 137 5.2.2 Issuer Alternative Name . . . . . . . . . . . . . . . . . . . 54 138 5.2.3 CRL Number . . . . . . . . . . . . . . . . . . . . . . . . . 54 139 5.2.4 Delta CRL Indicator . . . . . . . . . . . . . . . . . . . . . 55 140 5.2.5 Issuing Distribution Point . . . . . . . . . . . . . . . . . 58 141 5.2.6 Freshest CRL . . . . . . . . . . . . . . . . . . . . . . . . 59 142 5.3 CRL Entry Extensions . . . . . . . . . . . . . . . . . . . . . 59 143 5.3.1 Reason Code . . . . . . . . . . . . . . . . . . . . . . . . . 60 144 5.3.2 Hold Instruction Code . . . . . . . . . . . . . . . . . . . . 60 145 5.3.3 Invalidity Date . . . . . . . . . . . . . . . . . . . . . . . 61 146 5.3.4 Certificate Issuer . . . . . . . . . . . . . . . . . . . . . 61 147 6 Certificate Path Validation . . . . . . . . . . . . . . . . . . . 62 148 6.1 Basic Path Validation . . . . . . . . . . . . . . . . . . . . . 63 149 6.1.1 Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 150 6.1.2 Initialization . . . . . . . . . . . . . . . . . . . . . . . 66 151 6.1.3 Basic Certificate Processing . . . . . . . . . . . . . . . . 69 152 6.1.4 Preparation for Certificate i+1 . . . . . . . . . . . . . . . 74 153 6.1.5 Wrap-up procedure . . . . . . . . . . . . . . . . . . . . . . 77 154 6.1.6 Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . 79 155 6.2 Extending Path Validation . . . . . . . . . . . . . . . . . . . 79 156 6.3 CRL Validation . . . . . . . . . . . . . . . . . . . . . . . . 80 157 6.3.1 Revocation Inputs . . . . . . . . . . . . . . . . . . . . . . 80 158 6.3.2 Initialization and Revocation State Variables . . . . . . . . 81 159 6.3.3 CRL Processing . . . . . . . . . . . . . . . . . . . . . . . 81 160 7 References . . . . . . . . . . . . . . . . . . . . . . . . . . . 84 161 8 Intellectual Property Rights . . . . . . . . . . . . . . . . . . 87 162 9 Security Considerations . . . . . . . . . . . . . . . . . . . . . 87 163 Appendix A. ASN.1 Structures and OIDs . . . . . . . . . . . . . . . 91 164 A.1 Explicitly Tagged Module, 1988 Syntax . . . . . . . . . . . . . 91 165 A.2 Implicitly Tagged Module, 1988 Syntax . . . . . . . . . . . . . 104 166 Appendix B. ASN.1 Notes . . . . . . . . . . . . . . . . . . . . . . 111 167 Appendix C. Examples . . . . . . . . . . . . . . . . . . . . . . . 113 168 C.1 DSA Self-Signed Certificate . . . . . . . . . . . . . . . . . . 114 169 C.2 End Entity Certificate Using DSA . . . . . . . . . . . . . . . 117 170 C.3 End Entity Certificate Using RSA . . . . . . . . . . . . . . . 120 171 C.4 Certificate Revocation List . . . . . . . . . . . . . . . . . . 124 172 Appendix D. Author Addresses . . . . . . . . . . . . . . . . . . . 127 173 Appendix E. Full Copyright Statement . . . . . . . . . . . . . . . 127 174 1 Introduction 176 This specification is one part of a family of standards for the X.509 177 Public Key Infrastructure (PKI) for the Internet. This specification 178 is a standalone document; implementations of this standard may 179 proceed independent from the other parts. 181 This specification profiles the format and semantics of certificates 182 and certificate revocation lists for the Internet PKI. Procedures 183 are described for processing of certification paths in the Internet 184 environment. Encoding rules are provided for popular cryptographic 185 algorithms. Finally, ASN.1 modules are provided in the appendices 186 for all data structures defined or referenced. 188 The specification describes the requirements which inspire the 189 creation of this document and the assumptions which affect its scope 190 in Section 2. Section 3 presents an architectural model and 191 describes its relationship to previous IETF and ISO/IEC/ITU 192 standards. In particular, this document's relationship with the IETF 193 PEM specifications and the ISO/IEC/ITU X.509 documents are described. 195 The specification profiles the X.509 version 3 certificate in Section 196 4, and the X.509 version 2 certificate revocation list (CRL) in 197 Section 5. The profiles include the identification of ISO/IEC/ITU 198 and ANSI extensions which may be useful in the Internet PKI. The 199 profiles are presented in the 1988 Abstract Syntax Notation One 200 (ASN.1) rather than the 1997 ASN.1 syntax used in the ISO/IEC/ITU 201 standards. 203 This specification also includes path validation procedures in 204 Section 6. These procedures are based upon the ISO/IEC/ITU 205 definition, but the presentation assumes one or more self-signed 206 trusted CA certificates. Implementations are required to derive the 207 same results but are not required to use the specified procedures. 209 Procedures for identification and encoding of public key materials 210 and digital signatures are defined in [PKIXALGS]. Implementations of 211 this specification are not required to use any particular 212 cryptographic algorithms. However, conforming implementations which 213 use the algorithms identified in [PKIXALGS] MUST identify and encode 214 the public key materials and digital signatures as described in that 215 specification. 217 Finally, three appendices are provided to aid implementers. Appendix 218 A contains all ASN.1 structures defined or referenced within this 219 specification. As above, the material is presented in the 1988 220 ASN.1. Appendix B contains notes on less familiar features of the 221 ASN.1 notation used within this specification. Appendix C contains 222 examples of a conforming certificate and a conforming CRL. 224 2 Requirements and Assumptions 226 The goal of this specification is to develop a profile to facilitate 227 the use of X.509 certificates within Internet applications for those 228 communities wishing to make use of X.509 technology. Such 229 applications may include WWW, electronic mail, user authentication, 230 and IPsec. In order to relieve some of the obstacles to using X.509 231 certificates, this document defines a profile to promote the 232 development of certificate management systems; development of 233 application tools; and interoperability determined by policy. 235 Some communities will need to supplement, or possibly replace, this 236 profile in order to meet the requirements of specialized application 237 domains or environments with additional authorization, assurance, or 238 operational requirements. However, for basic applications, common 239 representations of frequently used attributes are defined so that 240 application developers can obtain necessary information without 241 regard to the issuer of a particular certificate or certificate 242 revocation list (CRL). 244 A certificate user should review the certificate policy generated by 245 the certification authority (CA) before relying on the authentication 246 or non-repudiation services associated with the public key in a 247 particular certificate. To this end, this standard does not 248 prescribe legally binding rules or duties. 250 As supplemental authorization and attribute management tools emerge, 251 such as attribute certificates, it may be appropriate to limit the 252 authenticated attributes that are included in a certificate. These 253 other management tools may provide more appropriate methods of 254 conveying many authenticated attributes. 256 2.1 Communication and Topology 258 The users of certificates will operate in a wide range of 259 environments with respect to their communication topology, especially 260 users of secure electronic mail. This profile supports users without 261 high bandwidth, real-time IP connectivity, or high connection 262 availability. In addition, the profile allows for the presence of 263 firewall or other filtered communication. 265 This profile does not assume the deployment of an X.500 Directory 266 system or a LDAP directory system. The profile does not prohibit the 267 use of an X.500 Directory or a LDAP directory; however, any means of 268 distributing certificates and certificate revocation lists (CRLs) may 269 be used. 271 2.2 Acceptability Criteria 273 The goal of the Internet Public Key Infrastructure (PKI) is to meet 274 the needs of deterministic, automated identification, authentication, 275 access control, and authorization functions. Support for these 276 services determines the attributes contained in the certificate as 277 well as the ancillary control information in the certificate such as 278 policy data and certification path constraints. 280 2.3 User Expectations 282 Users of the Internet PKI are people and processes who use client 283 software and are the subjects named in certificates. These uses 284 include readers and writers of electronic mail, the clients for WWW 285 browsers, WWW servers, and the key manager for IPsec within a router. 286 This profile recognizes the limitations of the platforms these users 287 employ and the limitations in sophistication and attentiveness of the 288 users themselves. This manifests itself in minimal user 289 configuration responsibility (e.g., trusted CA keys, rules), explicit 290 platform usage constraints within the certificate, certification path 291 constraints which shield the user from many malicious actions, and 292 applications which sensibly automate validation functions. 294 2.4 Administrator Expectations 296 As with user expectations, the Internet PKI profile is structured to 297 support the individuals who generally operate CAs. Providing 298 administrators with unbounded choices increases the chances that a 299 subtle CA administrator mistake will result in broad compromise. 300 Also, unbounded choices greatly complicate the software that process 301 and validate the certificates created by the CA. 303 3 Overview of Approach 305 Following is a simplified view of the architectural model assumed by 306 the PKIX specifications. 308 +---+ 309 | C | +------------+ 310 | e | <-------------------->| End entity | 311 | r | Operational +------------+ 312 | t | transactions ^ 313 | i | and management | Management 314 | f | transactions | transactions PKI 315 | i | | users 316 | c | v 317 | a | ======================= +--+------------+ ============== 318 | t | ^ ^ 319 | e | | | PKI 320 | | v | management 321 | & | +------+ | entities 322 | | <---------------------| RA |<----+ | 323 | C | Publish certificate +------+ | | 324 | R | | | 325 | L | | | 326 | | v v 327 | R | +------------+ 328 | e | <------------------------------| CA | 329 | p | Publish certificate +------------+ 330 | o | Publish CRL ^ ^ 331 | s | | | Management 332 | i | +------------+ | | transactions 333 | t | <--------------| CRL Issuer |<----+ | 334 | o | Publish CRL +------------+ v 335 | r | +------+ 336 | y | | CA | 337 +---+ +------+ 339 Figure 1 - PKI Entities 341 The components in this model are: 343 end entity: user of PKI certificates and/or end user system that 344 is the subject of a certificate; 345 CA: certification authority; 346 RA: registration authority, i.e., an optional system to 347 which a CA delegates certain management functions; 348 CRL issuer: an optional system to which a CA delegates the 349 publication of certificate revocation lists; 350 repository: a system or collection of distributed systems that 351 store certificates and CRLs and serves as a means of 352 distributing these certificates and CRLs to end 353 entities. 355 Note that an Attribute Authority (AA) might also choose to delegate 356 the publication of CRLs to a CRL issuer. 358 3.1 X.509 Version 3 Certificate 360 Users of a public key require confidence that the associated private 361 key is owned by the correct remote subject (person or system) with 362 which an encryption or digital signature mechanism will be used. 363 This confidence is obtained through the use of public key 364 certificates, which are data structures that bind public key values 365 to subjects. The binding is asserted by having a trusted CA 366 digitally sign each certificate. The CA may base this assertion upon 367 technical means (a.k.a., proof of possession through a challenge- 368 response protocol), presentation of the private key, or on an 369 assertion by the subject. A certificate has a limited valid lifetime 370 which is indicated in its signed contents. Because a certificate's 371 signature and timeliness can be independently checked by a 372 certificate-using client, certificates can be distributed via 373 untrusted communications and server systems, and can be cached in 374 unsecured storage in certificate-using systems. 376 ITU-T X.509 (formerly CCITT X.509) or ISO/IEC/ITU 9594-8, which was 377 first published in 1988 as part of the X.500 Directory 378 recommendations, defines a standard certificate format [X.509]. The 379 certificate format in the 1988 standard is called the version 1 (v1) 380 format. When X.500 was revised in 1993, two more fields were added, 381 resulting in the version 2 (v2) format. 383 The Internet Privacy Enhanced Mail (PEM) RFCs, published in 1993, 384 include specifications for a public key infrastructure based on X.509 385 v1 certificates [RFC 1422]. The experience gained in attempts to 386 deploy RFC 1422 made it clear that the v1 and v2 certificate formats 387 are deficient in several respects. Most importantly, more fields 388 were needed to carry information which PEM design and implementation 389 experience has proven necessary. In response to these new 390 requirements, ISO/IEC/ITU and ANSI X9 developed the X.509 version 3 391 (v3) certificate format. The v3 format extends the v2 format by 392 adding provision for additional extension fields. Particular 393 extension field types may be specified in standards or may be defined 394 and registered by any organization or community. In June 1996, 395 standardization of the basic v3 format was completed [X.509]. 397 ISO/IEC/ITU and ANSI X9 have also developed standard extensions for 398 use in the v3 extensions field [X.509][X9.55]. These extensions can 399 convey such data as additional subject identification information, 400 key attribute information, policy information, and certification path 401 constraints. 403 However, the ISO/IEC/ITU and ANSI X9 standard extensions are very 404 broad in their applicability. In order to develop interoperable 405 implementations of X.509 v3 systems for Internet use, it is necessary 406 to specify a profile for use of the X.509 v3 extensions tailored for 407 the Internet. It is one goal of this document to specify a profile 408 for Internet WWW, electronic mail, and IPsec applications. 409 Environments with additional requirements may build on this profile 410 or may replace it. 412 3.2 Certification Paths and Trust 414 A user of a security service requiring knowledge of a public key 415 generally needs to obtain and validate a certificate containing the 416 required public key. If the public-key user does not already hold an 417 assured copy of the public key of the CA that signed the certificate, 418 the CA's name, and related information (such as the validity period 419 or name constraints), then it might need an additional certificate to 420 obtain that public key. In general, a chain of multiple certificates 421 may be needed, comprising a certificate of the public key owner (the 422 end entity) signed by one CA, and zero or more additional 423 certificates of CAs signed by other CAs. Such chains, called 424 certification paths, are required because a public key user is only 425 initialized with a limited number of assured CA public keys. 427 There are different ways in which CAs might be configured in order 428 for public key users to be able to find certification paths. For 429 PEM, RFC 1422 defined a rigid hierarchical structure of CAs. There 430 are three types of PEM certification authority: 432 (a) Internet Policy Registration Authority (IPRA): This 433 authority, operated under the auspices of the Internet Society, 434 acts as the root of the PEM certification hierarchy at level 1. 435 It issues certificates only for the next level of authorities, 436 PCAs. All certification paths start with the IPRA. 438 (b) Policy Certification Authorities (PCAs): PCAs are at level 2 439 of the hierarchy, each PCA being certified by the IPRA. A PCA 440 shall establish and publish a statement of its policy with respect 441 to certifying users or subordinate certification authorities. 442 Distinct PCAs aim to satisfy different user needs. For example, 443 one PCA (an organizational PCA) might support the general 444 electronic mail needs of commercial organizations, and another PCA 445 (a high-assurance PCA) might have a more stringent policy designed 446 for satisfying legally binding digital signature requirements. 448 (c) Certification Authorities (CAs): CAs are at level 3 of the 449 hierarchy and can also be at lower levels. Those at level 3 are 450 certified by PCAs. CAs represent, for example, particular 451 organizations, particular organizational units (e.g., departments, 452 groups, sections), or particular geographical areas. 454 RFC 1422 furthermore has a name subordination rule which requires 455 that a CA can only issue certificates for entities whose names are 456 subordinate (in the X.500 naming tree) to the name of the CA itself. 457 The trust associated with a PEM certification path is implied by the 458 PCA name. The name subordination rule ensures that CAs below the PCA 459 are sensibly constrained as to the set of subordinate entities they 460 can certify (e.g., a CA for an organization can only certify entities 461 in that organization's name tree). Certificate user systems are able 462 to mechanically check that the name subordination rule has been 463 followed. 465 The RFC 1422 uses the X.509 v1 certificate formats. The limitations 466 of X.509 v1 required imposition of several structural restrictions to 467 clearly associate policy information or restrict the utility of 468 certificates. These restrictions included: 470 (a) a pure top-down hierarchy, with all certification paths 471 starting from IPRA; 473 (b) a naming subordination rule restricting the names of a CA's 474 subjects; and 476 (c) use of the PCA concept, which requires knowledge of 477 individual PCAs to be built into certificate chain verification 478 logic. Knowledge of individual PCAs was required to determine if 479 a chain could be accepted. 481 With X.509 v3, most of the requirements addressed by RFC 1422 can be 482 addressed using certificate extensions, without a need to restrict 483 the CA structures used. In particular, the certificate extensions 484 relating to certificate policies obviate the need for PCAs and the 485 constraint extensions obviate the need for the name subordination 486 rule. As a result, this document supports a more flexible 487 architecture, including: 489 (a) Certification paths start with a public key of a CA in a 490 user's own domain, or with the public key of the top of a 491 hierarchy. Starting with the public key of a CA in a user's own 492 domain has certain advantages. In some environments, the local 493 domain is the most trusted. 495 (b) Name constraints may be imposed through explicit inclusion of 496 a name constraints extension in a certificate, but are not 497 required. 499 (c) Policy extensions and policy mappings replace the PCA 500 concept, which permits a greater degree of automation. The 501 application can determine if the certification path is acceptable 502 based on the contents of the certificates instead of a priori 503 knowledge of PCAs. This permits automation of certificate chain 504 processing. 506 3.3 Revocation 508 When a certificate is issued, it is expected to be in use for its 509 entire validity period. However, various circumstances may cause a 510 certificate to become invalid prior to the expiration of the validity 511 period. Such circumstances include change of name, change of 512 association between subject and CA (e.g., an employee terminates 513 employment with an organization), and compromise or suspected 514 compromise of the corresponding private key. Under such 515 circumstances, the CA needs to revoke the certificate. 517 X.509 defines one method of certificate revocation. This method 518 involves each CA periodically issuing a signed data structure called 519 a certificate revocation list (CRL). A CRL is a time stamped list 520 identifying revoked certificates which is signed by a CA and made 521 freely available in a public repository. Each revoked certificate is 522 identified in a CRL by its certificate serial number. When a 523 certificate-using system uses a certificate (e.g., for verifying a 524 remote user's digital signature), that system not only checks the 525 certificate signature and validity but also acquires a suitably- 526 recent CRL and checks that the certificate serial number is not on 527 that CRL. The meaning of "suitably-recent" may vary with local 528 policy, but it usually means the most recently-issued CRL. A CA 529 issues a new CRL on a regular periodic basis (e.g., hourly, daily, or 530 weekly). An entry is added to the CRL as part of the next update 531 following notification of revocation. An entry may be removed from 532 the CRL after appearing on one regularly scheduled CRL issued beyond 533 the revoked certificate's validity period. 535 An advantage of this revocation method is that CRLs may be 536 distributed by exactly the same means as certificates themselves, 537 namely, via untrusted servers and untrusted communications. 539 One limitation of the CRL revocation method, using untrusted 540 communications and servers, is that the time granularity of 541 revocation is limited to the CRL issue period. For example, if a 542 revocation is reported now, that revocation will not be reliably 543 notified to certificate-using systems until all currently issued CRLs 544 are updated -- this may be up to one hour, one day, or one week 545 depending on the frequency that CRLs are issued. 547 As with the X.509 v3 certificate format, in order to facilitate 548 interoperable implementations from multiple vendors, the X.509 v2 CRL 549 format needs to be profiled for Internet use. It is one goal of this 550 document to specify that profile. However, this profile does not 551 require CAs to issue CRLs. Message formats and protocols supporting 552 on-line revocation notification are defined in other PKIX 553 specifications. On-line methods of revocation notification may be 554 applicable in some environments as an alternative to the X.509 CRL. 555 On-line revocation checking may significantly reduce the latency 556 between a revocation report and the distribution of the information 557 to relying parties. Once the CA accepts the report as authentic and 558 valid, any query to the on-line service will correctly reflect the 559 certificate validation impacts of the revocation. However, these 560 methods impose new security requirements: the certificate validator 561 needs to trust the on-line validation service while the repository 562 does not need to be trusted. 564 3.4 Operational Protocols 566 Operational protocols are required to deliver certificates and CRLs 567 (or status information) to certificate using client systems. 568 Provision is needed for a variety of different means of certificate 569 and CRL delivery, including distribution procedures based on LDAP, 570 HTTP, FTP, and X.500. Operational protocols supporting these 571 functions are defined in other PKIX specifications. These 572 specifications may include definitions of message formats and 573 procedures for supporting all of the above operational environments, 574 including definitions of or references to appropriate MIME content 575 types. 577 3.5 Management Protocols 579 Management protocols are required to support on-line interactions 580 between PKI user and management entities. For example, a management 581 protocol might be used between a CA and a client system with which a 582 key pair is associated, or between two CAs which cross-certify each 583 other. The set of functions which potentially need to be supported 584 by management protocols include: 586 (a) registration: This is the process whereby a user first makes 587 itself known to a CA (directly, or through an RA), prior to that 588 CA issuing a certificate or certificates for that user. 590 (b) initialization: Before a client system can operate securely 591 it is necessary to install key materials which have the 592 appropriate relationship with keys stored elsewhere in the 593 infrastructure. For example, the client needs to be securely 594 initialized with the public key and other assured information of 595 the trusted CA(s), to be used in validating certificate paths. 597 Furthermore, a client typically needs to be initialized with its 598 own key pair(s). 600 (c) certification: This is the process in which a CA issues a 601 certificate for a user's public key, and returns that certificate 602 to the user's client system and/or posts that certificate in a 603 repository. 605 (d) key pair recovery: As an option, user client key materials 606 (e.g., a user's private key used for encryption purposes) may be 607 backed up by a CA or a key backup system. If a user needs to 608 recover these backed up key materials (e.g., as a result of a 609 forgotten password or a lost key chain file), an on-line protocol 610 exchange may be needed to support such recovery. 612 (e) key pair update: All key pairs need to be updated regularly, 613 i.e., replaced with a new key pair, and new certificates issued. 615 (f) revocation request: An authorized person advises a CA of an 616 abnormal situation requiring certificate revocation. 618 (g) cross-certification: Two CAs exchange information used in 619 establishing a cross-certificate. A cross-certificate is a 620 certificate issued by one CA to another CA which contains a CA 621 signature key used for issuing certificates. 623 Note that on-line protocols are not the only way of implementing the 624 above functions. For all functions there are off-line methods of 625 achieving the same result, and this specification does not mandate 626 use of on-line protocols. For example, when hardware tokens are 627 used, many of the functions may be achieved as part of the physical 628 token delivery. Furthermore, some of the above functions may be 629 combined into one protocol exchange. In particular, two or more of 630 the registration, initialization, and certification functions can be 631 combined into one protocol exchange. 633 The PKIX series of specifications defines a set of standard message 634 formats supporting the above functions. The protocols for conveying 635 these messages in different environments (e.g., e-mail, file 636 transfer, and WWW) are described in those specifications. 638 4 Certificate and Certificate Extensions Profile 640 This section presents a profile for public key certificates that will 641 foster interoperability and a reusable PKI. This section is based 642 upon the X.509 v3 certificate format and the standard certificate 643 extensions defined in [X.509]. The ISO/IEC/ITU documents use the 644 1997 version of ASN.1; while this document uses the 1988 ASN.1 645 syntax, the encoded certificate and standard extensions are 646 equivalent. This section also defines private extensions required to 647 support a PKI for the Internet community. 649 Certificates may be used in a wide range of applications and 650 environments covering a broad spectrum of interoperability goals and 651 a broader spectrum of operational and assurance requirements. The 652 goal of this document is to establish a common baseline for generic 653 applications requiring broad interoperability and limited special 654 purpose requirements. In particular, the emphasis will be on 655 supporting the use of X.509 v3 certificates for informal Internet 656 electronic mail, IPsec, and WWW applications. 658 4.1 Basic Certificate Fields 660 The X.509 v3 certificate basic syntax is as follows. For signature 661 calculation, the certificate is encoded using the ASN.1 distinguished 662 encoding rules (DER) [X.208]. ASN.1 DER encoding is a tag, length, 663 value encoding system for each element. 665 Certificate ::= SEQUENCE { 666 tbsCertificate TBSCertificate, 667 signatureAlgorithm AlgorithmIdentifier, 668 signatureValue BIT STRING } 670 TBSCertificate ::= SEQUENCE { 671 version [0] EXPLICIT Version DEFAULT v1, 672 serialNumber CertificateSerialNumber, 673 signature AlgorithmIdentifier, 674 issuer Name, 675 validity Validity, 676 subject Name, 677 subjectPublicKeyInfo SubjectPublicKeyInfo, 678 issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL, 679 -- If present, version MUST be v2 or v3 680 subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL, 681 -- If present, version MUST be v2 or v3 682 extensions [3] EXPLICIT Extensions OPTIONAL 683 -- If present, version MUST be v3 684 } 686 Version ::= INTEGER { v1(0), v2(1), v3(2) } 688 CertificateSerialNumber ::= INTEGER 690 Validity ::= SEQUENCE { 691 notBefore Time, 692 notAfter Time } 694 Time ::= CHOICE { 695 utcTime UTCTime, 696 generalTime GeneralizedTime } 698 UniqueIdentifier ::= BIT STRING 700 SubjectPublicKeyInfo ::= SEQUENCE { 701 algorithm AlgorithmIdentifier, 702 subjectPublicKey BIT STRING } 704 Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension 706 Extension ::= SEQUENCE { 707 extnID OBJECT IDENTIFIER, 708 critical BOOLEAN DEFAULT FALSE, 709 extnValue OCTET STRING } 711 The following items describe the X.509 v3 certificate for use in the 712 Internet. 714 4.1.1 Certificate Fields 716 The Certificate is a SEQUENCE of three required fields. The fields 717 are described in detail in the following subsections. 719 4.1.1.1 tbsCertificate 721 The field contains the names of the subject and issuer, a public key 722 associated with the subject, a validity period, and other associated 723 information. The fields are described in detail in section 4.1.2; 724 the tbsCertificate MAY also include extensions which are described in 725 section 4.2. 727 4.1.1.2 signatureAlgorithm 729 The signatureAlgorithm field contains the identifier for the 730 cryptographic algorithm used by the CA to sign this certificate. 731 [PKIXALGS] lists supported signature algorithms, but other signature 732 algorithms MAY also be supported. 734 An algorithm identifier is defined by the following ASN.1 structure: 736 AlgorithmIdentifier ::= SEQUENCE { 737 algorithm OBJECT IDENTIFIER, 738 parameters ANY DEFINED BY algorithm OPTIONAL } 740 The algorithm identifier is used to identify a cryptographic 741 algorithm. The OBJECT IDENTIFIER component identifies the algorithm 742 (such as DSA with SHA-1). The contents of the optional parameters 743 field will vary according to the algorithm identified. [PKIXALGS] 744 lists supported algorithms, but other algorithms MAY also be 745 implemented. 747 This field MUST contain the same algorithm identifier as the 748 signature field in the sequence tbsCertificate (section 4.1.2.3). 750 4.1.1.3 signatureValue 752 The signatureValue field contains a digital signature computed upon 753 the ASN.1 DER encoded tbsCertificate. The ASN.1 DER encoded 754 tbsCertificate is used as the input to the signature function. This 755 signature value is then ASN.1 encoded as a BIT STRING and included in 756 the signature field. The details of this process are specified for 757 each of algorithms listed in [PKIXALGS]. 759 By generating this signature, a CA certifies the validity of the 760 information in the tbsCertificate field. In particular, the CA 761 certifies the binding between the public key material and the subject 762 of the certificate. 764 4.1.2 TBSCertificate 766 The sequence TBSCertificate contains information associated with the 767 subject of the certificate and the CA who issued it. Every 768 TBSCertificate contains the names of the subject and issuer, a public 769 key associated with the subject, a validity period, a version number, 770 and a serial number; some MAY contain optional unique identifier 771 fields. The remainder of this section describes the syntax and 772 semantics of these fields. A TBSCertificate MAY also include 773 extensions. Extensions for the Internet PKI are described in Section 774 4.2. 776 4.1.2.1 Version 778 This field describes the version of the encoded certificate. When 779 extensions are used, as expected in this profile, use X.509 version 3 780 (value is 2). If no extensions are present, but a UniqueIdentifier 781 is present, use version 2 (value is 1). If only basic fields are 782 present, use version 1 (the value is omitted from the certificate as 783 the default value). 785 Implementations SHOULD be prepared to accept any version certificate. 786 At a minimum, conforming implementations MUST recognize version 3 787 certificates. 789 Generation of version 2 certificates is not expected by 790 implementations based on this profile. 792 4.1.2.2 Serial number 794 The serial number MUST be a positive integer assigned by the CA to 795 each certificate. It MUST be unique for each certificate issued by a 796 given CA (i.e., the issuer name and serial number identify a unique 797 certificate). CAs MUST force the serialNumber to be a non-negative 798 integer. 800 Given the uniqueness requirements above, serial numbers can be 801 expected to contain long integers. Certificate users MUST be able to 802 handle serialNumber values up to 20 octets. Conformant CAs MUST NOT 803 use serialNumber values longer than 20 octets. 805 Note: Non-conforming CAs MAY issue certificates with serial numbers 806 that are negative, or zero. Certificate users SHOULD be prepared to 807 handle such certificates. 809 4.1.2.3 Signature 811 This field contains the algorithm identifier for the algorithm used 812 by the CA to sign the certificate. 814 This field MUST contain the same algorithm identifier as the 815 signatureAlgorithm field in the sequence Certificate (section 816 4.1.1.2). The contents of the optional parameters field will vary 817 according to the algorithm identified. [PKIXALGS] lists the 818 supported signature algorithms. 820 4.1.2.4 Issuer 822 The issuer field identifies the entity who has signed and issued the 823 certificate. The issuer field MUST contain a non-empty distinguished 824 name (DN). The issuer field is defined as the X.501 type Name 825 [X.501]. Name is defined by the following ASN.1 structures: 827 Name ::= CHOICE { 828 RDNSequence } 830 RDNSequence ::= SEQUENCE OF RelativeDistinguishedName 832 RelativeDistinguishedName ::= 833 SET OF AttributeTypeAndValue 835 AttributeTypeAndValue ::= SEQUENCE { 836 type AttributeType, 837 value AttributeValue } 839 AttributeType ::= OBJECT IDENTIFIER 841 AttributeValue ::= ANY DEFINED BY AttributeType 843 DirectoryString ::= CHOICE { 844 teletexString TeletexString (SIZE (1..MAX)), 845 printableString PrintableString (SIZE (1..MAX)), 846 universalString UniversalString (SIZE (1..MAX)), 847 utf8String UTF8String (SIZE (1..MAX)), 848 bmpString BMPString (SIZE (1..MAX)) } 850 The Name describes a hierarchical name composed of attributes, such 851 as country name, and corresponding values, such as US. The type of 852 the component AttributeValue is determined by the AttributeType; in 853 general it will be a DirectoryString. 855 The DirectoryString type is defined as a choice of PrintableString, 856 TeletexString, BMPString, UTF8String, and UniversalString. The 857 UTF8String encoding [RFC 2279] is the preferred encoding, and all 858 certificates issued after December 31, 2003 MUST use the UTF8String 859 encoding of DirectoryString (except as noted below). Until that 860 date, conforming CAs MUST choose from the following options when 861 creating a distinguished name, including their own: 863 (a) if the character set is sufficient, the string MAY be 864 represented as a PrintableString; 866 (b) failing (a), if the BMPString character set is sufficient the 867 string MAY be represented as a BMPString; and 869 (c) failing (a) and (b), the string MUST be represented as a 870 UTF8String. If (a) or (b) is satisfied, the CA MAY still choose 871 to represent the string as a UTF8String. 873 Exceptions to the December 31, 2003 UTF8 encoding requirements are as 874 follows: 876 (a) CAs MAY issue "name rollover" certificates to support an 877 orderly migration to UTF8String encoding. Such certificates would 878 include the CA's UTF8String encoded name as issuer and and the old 879 name encoding as subject, or vice-versa. 881 (b) As stated in section 4.1.2.6, the subject field MUST be 882 populated with a non-empty distinguished name matching the 883 contents of the issuer field in all certificates issued by the 884 subject CA regardless of encoding. 886 The TeletexString and UniversalString are included for backward 887 compatibility, and SHOULD NOT be used for certificates for new 888 subjects. However, these types MAY be used in certificates where the 889 name was previously established. Certificate users SHOULD be 890 prepared to receive certificates with these types. 892 In addition, many legacy implementations support names encoded in the 893 ISO 8859-1 character set (Latin1String) but tag them as 894 TeletexString. The Latin1String includes characters used in Western 895 European countries which are not part of the TeletexString charcter 896 set. Implementations that process TeletexString SHOULD be prepared 897 to handle the entire ISO 8859-1 character set.[ISO 8859-1] 899 As noted above, distinguished names are composed of attributes. This 900 specification does not restrict the set of attribute types that may 901 appear in names. However, conforming implementations MUST be 902 prepared to receive certificates with issuer names containing the set 903 of attribute types defined below. This specification RECOMMENDS 904 support for additional attribute types. 906 Standard sets of attributes have been defined in the X.500 series of 907 specifications.[X.520] Implementations of this specification MUST be 908 prepared to receive the following standard attribute types in issuer 909 and subject (section 4.1.2.6) names: 911 * country, 912 * organization, 913 * organizational-unit, 914 * distinguished name qualifier, 915 * state or province name, 916 * common name (e.g., "Susan Housley"), and 917 * serial number. 919 In addition, implementations of this specification SHOULD be prepared 920 to receive the following standard attribute types in issuer and 921 subject names: 923 * locality, 924 * title, 925 * surname, 926 * given name, 927 * initials, 928 * pseudonym, and 929 * generation qualifier (e.g., "Jr.", "3rd", or "IV"). 931 The syntax and associated object identifiers (OIDs) for these 932 attribute types are provided in the ASN.1 modules in Appendix A. 934 In addition, implementations of this specification MUST be prepared 935 to receive the domainComponent attribute, as defined in [RFC 2247]. 936 The Domain (Nameserver) System (DNS) provides a hierarchical resource 937 labeling system. This attribute provides a convenient mechanism for 938 organizations that wish to use DNs that parallel their DNS names. 939 This is not a replacement for the dNSName component of the 940 alternative name field. Implementations are not required to convert 941 such names into DNS names. The syntax and associated OID for this 942 attribute type is provided in the ASN.1 modules in Appendix A. 944 Certificate users MUST be prepared to process the issuer 945 distinguished name and subject distinguished name (section 4.1.2.6) 946 fields to perform name chaining for certification path validation 947 (section 6). Name chaining is performed by matching the issuer 948 distinguished name in one certificate with the subject name in a CA 949 certificate. 951 This specification requires only a subset of the name comparison 952 functionality specified in the X.500 series of specifications. The 953 requirements for conforming implementations are as follows: 955 (a) attribute values encoded in different types (e.g., 956 PrintableString and BMPString) MAY be assumed to represent 957 different strings; 959 (b) attribute values in types other than PrintableString are case 960 sensitive (this permits matching of attribute values as binary 961 objects); 963 (c) attribute values in PrintableString are not case sensitive 964 (e.g., "Marianne Swanson" is the same as "MARIANNE SWANSON"); and 966 (d) attribute values in PrintableString are compared after 967 removing leading and trailing white space and converting internal 968 substrings of one or more consecutive white space characters to a 969 single space. 971 These name comparison rules permit a certificate user to validate 972 certificates issued using languages or encodings unfamiliar to the 973 certificate user. 975 In addition, implementations of this specification MAY use these 976 comparison rules to process unfamiliar attribute types for name 977 chaining. This allows implementations to process certificates with 978 unfamiliar attributes in the issuer name. 980 Note that the comparison rules defined in the X.500 series of 981 specifications indicate that the character sets used to encode data 982 in distinguished names are irrelevant. The characters themselves are 983 compared without regard to encoding. Implementations of the profile 984 are permitted to use the comparison algorithm defined in the X.500 985 series. Such an implementation will recognize a superset of name 986 matches recognized by the algorithm specified above. 988 4.1.2.5 Validity 990 The certificate validity period is the time interval during which the 991 CA warrants that it will maintain information about the status of the 992 certificate. The field is represented as a SEQUENCE of two dates: 993 the date on which the certificate validity period begins (notBefore) 994 and the date on which the certificate validity period ends 995 (notAfter). Both notBefore and notAfter may be encoded as UTCTime or 996 GeneralizedTime. 998 CAs conforming to this profile MUST always encode certificate 999 validity dates through the year 2049 as UTCTime; certificate validity 1000 dates in 2050 or later MUST be encoded as GeneralizedTime. 1002 The validity period for a certificate is the period of time from 1003 notBefore through notAfter, inclusive. 1005 4.1.2.5.1 UTCTime 1007 The universal time type, UTCTime, is a standard ASN.1 type intended 1008 for representation of dates and time. UTCTime specifies the year 1009 through the two low order digits and time is specified to the 1010 precision of one minute or one second. UTCTime includes either Z 1011 (for Zulu, or Greenwich Mean Time) or a time differential. 1013 For the purposes of this profile, UTCTime values MUST be expressed 1014 Greenwich Mean Time (Zulu) and MUST include seconds (i.e., times are 1015 YYMMDDHHMMSSZ), even where the number of seconds is zero. Conforming 1016 systems MUST interpret the year field (YY) as follows: 1018 Where YY is greater than or equal to 50, the year SHALL be 1019 interpreted as 19YY; and 1021 Where YY is less than 50, the year SHALL be interpreted as 20YY. 1023 4.1.2.5.2 GeneralizedTime 1025 The generalized time type, GeneralizedTime, is a standard ASN.1 type 1026 for variable precision representation of time. Optionally, the 1027 GeneralizedTime field can include a representation of the time 1028 differential between local and Greenwich Mean Time. 1030 For the purposes of this profile, GeneralizedTime values MUST be 1031 expressed Greenwich Mean Time (Zulu) and MUST include seconds (i.e., 1032 times are YYYYMMDDHHMMSSZ), even where the number of seconds is zero. 1033 GeneralizedTime values MUST NOT include fractional seconds. 1035 4.1.2.6 Subject 1037 The subject field identifies the entity associated with the public 1038 key stored in the subject public key field. The subject name MAY be 1039 carried in the subject field and/or the subjectAltName extension. If 1040 the subject is a CA (e.g., the basic constraints extension, as 1041 discussed in 4.2.1.10, is present and the value of cA is TRUE,) then 1042 the subject field MUST be populated with a non-empty distinguished 1043 name matching the contents of the issuer field (section 4.1.2.4) in 1044 all certificates issued by the subject CA. If subject naming 1045 information is present only in the subjectAltName extension (e.g., a 1046 key bound only to an email address or URI), then the subject name 1047 MUST be an empty sequence and the subjectAltName extension MUST be 1048 critical. 1050 Where it is non-empty, the subject field MUST contain an X.500 1051 distinguished name (DN). The DN MUST be unique for each subject 1052 entity certified by the one CA as defined by the issuer name field. 1053 A CA MAY issue more than one certificate with the same DN to the same 1054 subject entity. 1056 The subject name field is defined as the X.501 type Name. 1057 Implementation requirements for this field are those defined for the 1058 issuer field (section 4.1.2.4). When encoding attribute values of 1059 type DirectoryString, the encoding rules for the issuer field MUST be 1060 implemented. Implementations of this specification MUST be prepared 1061 to receive subject names containing the attribute types required for 1062 the issuer field. Implementations of this specification SHOULD be 1063 prepared to receive subject names containing the recommended 1064 attribute types for the issuer field. The syntax and associated 1065 object identifiers (OIDs) for these attribute types are provided in 1066 the ASN.1 modules in Appendix A. Implementations of this 1067 specification MAY use these comparison rules to process unfamiliar 1068 attribute types (i.e., for name chaining). This allows 1069 implementations to process certificates with unfamiliar attributes in 1070 the subject name. 1072 In addition, legacy implementations exist where an RFC 822 name is 1073 embedded in the subject distinguished name as an EmailAddress 1074 attribute. The attribute value for EmailAddress is of type IA5String 1075 to permit inclusion of the character '@', which is not part of the 1076 PrintableString character set. EmailAddress attribute values are not 1077 case sensitive (e.g., "fanfeedback@redsox.com" is the same as 1078 "FANFEEDBACK@REDSOX.COM"). 1080 Conforming implementations generating new certificates with 1081 electronic mail addresses MUST use the rfc822Name in the subject 1082 alternative name field (section 4.2.1.7) to describe such identities. 1083 Simultaneous inclusion of the EmailAddress attribute in the subject 1084 distinguished name to support legacy implementations is deprecated 1085 but permitted. 1087 4.1.2.7 Subject Public Key Info 1089 This field is used to carry the public key and identify the algorithm 1090 with which the key is used (e.g., RSA, DSA, or Diffie-Hellman). The 1091 algorithm is identified using the AlgorithmIdentifier structure 1092 specified in section 4.1.1.2. The object identifiers for the 1093 supported algorithms and the methods for encoding the public key 1094 materials (public key and parameters) are specified in [PKIXALGS]. 1096 4.1.2.8 Unique Identifiers 1098 These fields MUST only appear if the version is 2 or 3 (section 1099 4.1.2.1). These fields MUST NOT appear if the version is 1. The 1100 subject and issuer unique identifiers are present in the certificate 1101 to handle the possibility of reuse of subject and/or issuer names 1102 over time. This profile RECOMMENDS that names not be reused for 1103 different entities and that Internet certificates not make use of 1104 unique identifiers. CAs conforming to this profile SHOULD NOT 1105 generate certificates with unique identifiers. Applications 1106 conforming to this profile SHOULD be capable of parsing unique 1107 identifiers and making comparisons. 1109 4.1.2.9 Extensions 1111 This field MUST only appear if the version is 3 (section 4.1.2.1). 1112 If present, this field is a SEQUENCE of one or more certificate 1113 extensions. The format and content of certificate extensions in the 1114 Internet PKI is defined in section 4.2. 1116 4.2 Certificate Extensions 1118 The extensions defined for X.509 v3 certificates provide methods for 1119 associating additional attributes with users or public keys and for 1120 managing the certification hierarchy. The X.509 v3 certificate 1121 format also allows communities to define private extensions to carry 1122 information unique to those communities. Each extension in a 1123 certificate is designated as either critical or non-critical. A 1124 certificate using system MUST reject the certificate if it encounters 1125 a critical extension it does not recognize; however, a non-critical 1126 extension MAY be ignored if it is not recognized. The following 1127 sections present recommended extensions used within Internet 1128 certificates and standard locations for information. Communities MAY 1129 elect to use additional extensions; however, caution SHOULD be 1130 exercised in adopting any critical extensions in certificates which 1131 might prevent use in a general context. 1133 Each extension includes an OID and an ASN.1 structure. When an 1134 extension appears in a certificate, the OID appears as the field 1135 extnID and the corresponding ASN.1 encoded structure is the value of 1136 the octet string extnValue. Only one instance of a particular 1137 extension MUST appear in a particular certificate. For example, a 1138 certificate may contain only one authority key identifier extension 1139 (section 4.2.1.1). An extension includes the boolean critical, with 1140 a default value of FALSE. The text for each extension specifies the 1141 acceptable values for the critical field. 1143 Conforming CAs MUST support key identifiers (sections 4.2.1.1 and 1144 4.2.1.2), basic constraints (section 4.2.1.10), key usage (section 1145 4.2.1.3), and certificate policies (section 4.2.1.5) extensions. If 1146 the CA issues certificates with an empty sequence for the subject 1147 field, the CA MUST support the subject alternative name extension 1148 (section 4.2.1.7). Support for the remaining extensions is OPTIONAL. 1149 Conforming CAs MAY support extensions that are not identified within 1150 this specification; certificate issuers are cautioned that marking 1151 such extensions as critical may inhibit interoperability. 1153 At a minimum, applications conforming to this profile MUST recognize 1154 the following extensions: key usage (section 4.2.1.3), certificate 1155 policies (section 4.2.1.5), the subject alternative name (section 1156 4.2.1.7), basic constraints (section 4.2.1.10), name constraints 1157 (section 4.2.1.11), policy constraints (section 4.2.1.12), extended 1158 key usage (section 4.2.1.13), and inhibit any-policy (section 1159 4.2.1.15). 1161 In addition, applications conforming to this profile SHOULD recognize 1162 the authority and subject key identifier (sections 4.2.1.1 and 1163 4.2.1.2), and policy mapping (section 4.2.1.6) extensions. 1165 4.2.1 Standard Extensions 1167 This section identifies standard certificate extensions defined in 1168 [X.509] for use in the Internet PKI. Each extension is associated 1169 with an OID defined in [X.509]. These OIDs are members of the id-ce 1170 arc, which is defined by the following: 1172 id-ce OBJECT IDENTIFIER ::= {joint-iso-ccitt(2) ds(5) 29} 1174 4.2.1.1 Authority Key Identifier 1176 The authority key identifier extension provides a means of 1177 identifying the public key corresponding to the private key used to 1178 sign a certificate. This extension is used where an issuer has 1179 multiple signing keys (either due to multiple concurrent key pairs or 1180 due to changeover). The identification MAY be based on either the 1181 key identifier (the subject key identifier in the issuer's 1182 certificate) or on the issuer name and serial number. 1184 The keyIdentifier field of the authorityKeyIdentifier extension MUST 1185 be included in all certificates generated by conforming CAs to 1186 facilitate chain building. There is one exception; where a CA 1187 distributes its public key in the form of a "self-signed" 1188 certificate, the authority key identifier MAY be omitted. The 1189 signature on a self-signed certificate is generated with the private 1190 key associated with the certificate's subject public key. (This 1191 proves that the issuer possesses both the public and private keys.) 1192 In this case, the subject and authority key identifiers would be 1193 identical, but only the subject key identifier is needed for 1194 certification path building. 1196 The value of the keyIdentifier field SHOULD be derived from the 1197 public key used to verify the certificate's signature or a method 1198 that generates unique values. Two common methods for generating key 1199 identifiers from the public key are described in (sec. 4.2.1.2). One 1200 common method for generating unique values is described in (sec. 1201 4.2.1.2). Where a key identifier has not been previously 1202 established, this specification recommends use of one of these 1203 methods for generating keyIdentifiers. 1205 This profile recommends support for the key identifier method by all 1206 certificate users. 1208 This extension MUST NOT be marked critical. 1210 id-ce-authorityKeyIdentifier OBJECT IDENTIFIER ::= { id-ce 35 } 1212 AuthorityKeyIdentifier ::= SEQUENCE { 1213 keyIdentifier [0] KeyIdentifier OPTIONAL, 1214 authorityCertIssuer [1] GeneralNames OPTIONAL, 1215 authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL } 1217 KeyIdentifier ::= OCTET STRING 1219 4.2.1.2 Subject Key Identifier 1221 The subject key identifier extension provides a means of identifying 1222 certificates that contain a particular public key. 1224 To facilitate chain building, this extension MUST appear in all 1225 conforming CA certificates, that is, all certificates including the 1226 basic constraints extension (section 4.2.1.10) where the value of cA 1227 is TRUE. The value of the subject key identifier MUST be the value 1228 placed in the key identifier field of the Authority Key Identifier 1229 extension (section 4.2.1.1) of certificates issued by the subject of 1230 this certificate. 1232 For CA certificates, subject key identifiers SHOULD be derived from 1233 the public key or a method that generates unique values. The key 1234 identifier is an explicit value placed in the certificate by the 1235 issuer, not a value generated by a certificate user. Two common 1236 methods for generating key identifiers from the public key are: 1238 (1) The keyIdentifier is composed of the 160-bit SHA-1 hash of the 1239 value of the BIT STRING subjectPublicKey (excluding the tag, 1240 length, and number of unused bits). 1242 (2) The keyIdentifier is composed of a four bit type field with 1243 the value 0100 followed by the least significant 60 bits of the 1244 SHA-1 hash of the value of the BIT STRING subjectPublicKey 1245 (excluding the tag, length, and number of unused bit string bits). 1247 One common method for generating unique values is a monotonically 1248 increasing sequence of integers. 1250 For end entity certificates, the subject key identifier extension 1251 provides a means for identifying certificates containing the 1252 particular public key used in an application. Where an end entity 1253 has obtained multiple certificates, especially from multiple CAs, the 1254 subject key identifier provides a means to quickly identify the set 1255 of certificates containing a particular public key. To assist 1256 applications in identifying the appropriate end entity certificate, 1257 this extension SHOULD be included in all end entity certificates. 1259 For end entity certificates, subject key identifiers SHOULD be 1260 derived from the public key. Two common methods for generating key 1261 identifiers from the public key are identified above. 1263 Where a key identifier has not been previously established, this 1264 specification recommends use of one of these methods for generating 1265 keyIdentifiers. 1267 This extension MUST NOT be marked critical. 1269 id-ce-subjectKeyIdentifier OBJECT IDENTIFIER ::= { id-ce 14 } 1271 SubjectKeyIdentifier ::= KeyIdentifier 1273 4.2.1.3 Key Usage 1275 The key usage extension defines the purpose (e.g., encipherment, 1276 signature, certificate signing) of the key contained in the 1277 certificate. The usage restriction might be employed when a key that 1278 could be used for more than one operation is to be restricted. For 1279 example, when an RSA key should be used only to verify signatures on 1280 objects other than public key certificates and CRLs, the 1281 digitalSignature and/or nonRepudiation bits would be asserted. 1282 Likewise, when an RSA key should be used only for key management, the 1283 keyEncipherment bit would be asserted. 1285 This extension MUST appear in certificates that contain public keys 1286 that are used to validate digital signatures on other public key 1287 certificates or CRLs. When this extension appears, it SHOULD be 1288 marked critical. 1290 id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } 1292 KeyUsage ::= BIT STRING { 1293 digitalSignature (0), 1294 nonRepudiation (1), 1295 keyEncipherment (2), 1296 dataEncipherment (3), 1297 keyAgreement (4), 1298 keyCertSign (5), 1299 cRLSign (6), 1300 encipherOnly (7), 1301 decipherOnly (8) } 1303 Bits in the KeyUsage type are used as follows: 1305 The digitalSignature bit is asserted when the subject public key 1306 is used with a digital signature mechanism to support security 1307 services other than non-repudiation (bit 1), certificate signing 1308 (bit 5), or CRL signing (bit 6). Digital signature mechanisms are 1309 often used for entity authentication and data origin 1310 authentication with integrity. 1312 The nonRepudiation bit is asserted when the subject public key is 1313 used to verify digital signatures used to provide a non- 1314 repudiation service which protects against the signing entity 1315 falsely denying some action, excluding certificate or CRL signing. 1316 In the case of later conflict, a reliable third party may 1317 determine the authenticity of the signed data. 1319 Further distinctions between the digitalSignature and 1320 nonRepudiation bits may be provided in specific certificate 1321 policies. 1323 The keyEncipherment bit is asserted when the subject public key is 1324 used for key transport. For example, when an RSA key is to be 1325 used for key management, then this bit is set. 1327 The dataEncipherment bit is asserted when the subject public key 1328 is used for enciphering user data, other than cryptographic keys. 1330 The keyAgreement bit is asserted when the subject public key is 1331 used for key agreement. For example, when a Diffie-Hellman key is 1332 to be used for key management, then this bit is set. 1334 The keyCertSign bit is asserted when the subject public key is 1335 used for verifying a signature on public key certificates. If the 1336 keyCertSign bit is asserted, then the cA bit in the basic 1337 constraints extension (section 4.2.1.10) MUST also be asserted. 1339 The cRLSign bit is asserted when the subject public key is used 1340 for verifying a signature on certificate revocation list (e.g., a 1341 CRL, delta CRL, or an ARL). This bit MUST be asserted in 1342 certificates that are used to verify signatures on CRLs. 1344 The meaning of the encipherOnly bit is undefined in the absence of 1345 the keyAgreement bit. When the encipherOnly bit is asserted and 1346 the keyAgreement bit is also set, the subject public key may be 1347 used only for enciphering data while performing key agreement. 1349 The meaning of the decipherOnly bit is undefined in the absence of 1350 the keyAgreement bit. When the decipherOnly bit is asserted and 1351 the keyAgreement bit is also set, the subject public key may be 1352 used only for deciphering data while performing key agreement. 1354 This profile does not restrict the combinations of bits that may be 1355 set in an instantiation of the keyUsage extension. However, 1356 appropriate values for keyUsage extensions for particular algorithms 1357 are specified in [PKIXALGS]. 1359 4.2.1.4 Private Key Usage Period 1361 This profile RECOMMENDS against the use of this extension. CAs 1362 conforming to this profile MUST NOT generate certificates that 1363 include a critical private key usage period extension. 1365 The private key usage period extension allows the certificate issuer 1366 to specify a different validity period for the private key than the 1367 certificate. This extension is intended for use with digital 1368 signature keys. This extension consists of two optional components, 1369 notBefore and notAfter. The private key associated with the 1370 certificate SHOULD NOT be used to sign objects before or after the 1371 times specified by the two components, respectively. CAs conforming 1372 to this profile MUST NOT generate certificates with private key usage 1373 period extensions unless at least one of the two components is 1374 present. 1376 Where used, notBefore and notAfter are represented as GeneralizedTime 1377 and MUST be specified and interpreted as defined in section 1378 4.1.2.5.2. 1380 id-ce-privateKeyUsagePeriod OBJECT IDENTIFIER ::= { id-ce 16 } 1382 PrivateKeyUsagePeriod ::= SEQUENCE { 1383 notBefore [0] GeneralizedTime OPTIONAL, 1384 notAfter [1] GeneralizedTime OPTIONAL } 1386 4.2.1.5 Certificate Policies 1388 The certificate policies extension contains a sequence of one or more 1389 policy information terms, each of which consists of an object 1390 identifier (OID) and optional qualifiers. Optional qualifiers, which 1391 MAY be present, are not expected to change the definition of the 1392 policy. 1394 In an end entity certificate, these policy information terms indicate 1395 the policy under which the certificate has been issued and the 1396 purposes for which the certificate may be used. In a CA certificate, 1397 these policy information terms limit the set of policies for 1398 certification paths which include this certificate. When a CA does 1399 not wish to limit the set of policies for certification paths which 1400 include this certificate, they MAY assert the special policy 1401 anyPolicy, with a value of { 2 5 29 32 0 }. 1403 Applications with specific policy requirements are expected to have a 1404 list of those policies which they will accept and to compare the 1405 policy OIDs in the certificate to that list. If this extension is 1406 critical, the path validation software MUST be able to interpret this 1407 extension (including the optional qualifier), or MUST reject the 1408 certificate. 1410 To promote interoperability, this profile RECOMMENDS that policy 1411 information terms consist of only an OID. Where an OID alone is 1412 insufficient, this profile strongly recommends that use of qualifiers 1413 be limited to those identified in this section. When qualifiers are 1414 used with the special policy anyPolicy, they MUST be limited to the 1415 qualifiers identified in this section. 1417 This specification defines two policy qualifier types for use by 1418 certificate policy writers and certificate issuers. The qualifier 1419 types are the CPS Pointer and User Notice qualifiers. 1421 The CPS Pointer qualifier contains a pointer to a Certification 1422 Practice Statement (CPS) published by the CA. The pointer is in the 1423 form of a URI. Processing requirements for this qualifier are a 1424 local matter. No action is mandated by this specification regardless 1425 of the criticality value asserted for the extension. 1427 User notice is intended for display to a relying party when a 1428 certificate is used. The application software SHOULD display all 1429 user notices in all certificates of the certification path used, 1430 except that if a notice is duplicated only one copy need be 1431 displayed. To prevent such duplication, this qualifier SHOULD only 1432 be present in end entity certificates and CA certificates issued to 1433 other organizations. 1435 The user notice has two optional fields: the noticeRef field and the 1436 explicitText field. 1438 The noticeRef field, if used, names an organization and 1439 identifies, by number, a particular textual statement prepared by 1440 that organization. For example, it might identify the 1441 organization "CertsRUs" and notice number 1. In a typical 1442 implementation, the application software will have a notice file 1443 containing the current set of notices for CertsRUs; the 1444 application will extract the notice text from the file and display 1445 it. Messages MAY be multilingual, allowing the software to select 1446 the particular language message for its own environment. 1448 An explicitText field includes the textual statement directly in 1449 the certificate. The explicitText field is a string with a 1450 maximum size of 200 characters. 1452 If both the noticeRef and explicitText options are included in the 1453 one qualifier and if the application software can locate the notice 1454 text indicated by the noticeRef option then that text SHOULD be 1455 displayed; otherwise, the explicitText string SHOULD be displayed. 1457 id-ce-certificatePolicies OBJECT IDENTIFIER ::= { id-ce 32 } 1458 anyPolicy OBJECT IDENTIFIER ::= { id-ce-certificate-policies 0 } 1460 certificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation 1462 PolicyInformation ::= SEQUENCE { 1463 policyIdentifier CertPolicyId, 1464 policyQualifiers SEQUENCE SIZE (1..MAX) OF 1465 PolicyQualifierInfo OPTIONAL } 1467 CertPolicyId ::= OBJECT IDENTIFIER 1469 PolicyQualifierInfo ::= SEQUENCE { 1470 policyQualifierId PolicyQualifierId, 1471 qualifier ANY DEFINED BY policyQualifierId } 1473 -- policyQualifierIds for Internet policy qualifiers 1475 id-qt OBJECT IDENTIFIER ::= { id-pkix 2 } 1476 id-qt-cps OBJECT IDENTIFIER ::= { id-qt 1 } 1477 id-qt-unotice OBJECT IDENTIFIER ::= { id-qt 2 } 1479 PolicyQualifierId ::= 1480 OBJECT IDENTIFIER ( id-qt-cps | id-qt-unotice ) 1482 Qualifier ::= CHOICE { 1483 cPSuri CPSuri, 1484 userNotice UserNotice } 1486 CPSuri ::= IA5String 1488 UserNotice ::= SEQUENCE { 1489 noticeRef NoticeReference OPTIONAL, 1490 explicitText DisplayText OPTIONAL} 1492 NoticeReference ::= SEQUENCE { 1493 organization DisplayText, 1494 noticeNumbers SEQUENCE OF INTEGER } 1496 DisplayText ::= CHOICE { 1497 ia5String IA5String (SIZE (1..200)), 1498 visibleString VisibleString (SIZE (1..200)), 1499 bmpString BMPString (SIZE (1..200)), 1500 utf8String UTF8String (SIZE (1..200)) } 1502 4.2.1.6 Policy Mappings 1504 This extension is used in CA certificates. It lists one or more 1505 pairs of OIDs; each pair includes an issuerDomainPolicy and a 1506 subjectDomainPolicy. The pairing indicates the issuing CA considers 1507 its issuerDomainPolicy equivalent to the subject CA's 1508 subjectDomainPolicy. 1510 The issuing CA's users might accept an issuerDomainPolicy for certain 1511 applications. The policy mapping defines the list of policies 1512 associated with the subject CA that may be accepted as comparable to 1513 the issuerDomainPolicy. 1515 Each issuerDomainPolicy named in the policy mapping extension SHOULD 1516 also be asserted in a certificate policies extension in the same 1517 certificate. Policies SHOULD NOT be mapped either to or from the 1518 special value anyPolicy (section 4.2.1.5). 1520 This extension MAY be supported by CAs and/or applications, and it 1521 MUST be non-critical. 1523 id-ce-policyMappings OBJECT IDENTIFIER ::= { id-ce 33 } 1525 PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE { 1526 issuerDomainPolicy CertPolicyId, 1527 subjectDomainPolicy CertPolicyId } 1529 4.2.1.7 Subject Alternative Name 1531 The subject alternative names extension allows additional identities 1532 to be bound to the subject of the certificate. Defined options 1533 include an Internet electronic mail address, a DNS name, an IP 1534 address, and a uniform resource identifier (URI). Other options 1535 exist, including completely local definitions. Multiple name forms, 1536 and multiple instances of each name form, MAY be included. Whenever 1537 such identities are to be bound into a certificate, the subject 1538 alternative name (or issuer alternative name) extension MUST be used; 1539 however, a DNS name MAY be represented in the subject field using the 1540 domainComponent attribute as described in section 4.1.2.4. 1542 Because the subject alternative name is considered to be definitively 1543 bound to the public key, all parts of the subject alternative name 1544 MUST be verified by the CA. 1546 Further, if the only subject identity included in the certificate is 1547 an alternative name form (e.g., an electronic mail address), then the 1548 subject distinguished name MUST be empty (an empty sequence), and the 1549 subjectAltName extension MUST be present. If the subject field 1550 contains an empty sequence, the subjectAltName extension MUST be 1551 marked critical. 1553 When the subjectAltName extension contains an Internet mail address, 1554 the address MUST be included as an rfc822Name. The format of an 1555 rfc822Name is an "addr-spec" as defined in RFC 822 [RFC 822]. An 1556 addr-spec has the form "local-part@domain". Note that an addr-spec 1557 has no phrase (such as a common name) before it, has no comment (text 1558 surrounded in parentheses) after it, and is not surrounded by "<" and 1559 ">". Note that while upper and lower case letters are allowed in an 1560 RFC 822 addr-spec, no significance is attached to the case. 1562 When the subjectAltName extension contains a iPAddress, the address 1563 MUST be stored in the octet string in "network byte order," as 1564 specified in RFC 791 [RFC 791]. The least significant bit (LSB) of 1565 each octet is the LSB of the corresponding byte in the network 1566 address. For IP Version 4, as specified in RFC 791, the octet string 1567 MUST contain exactly four octets. For IP Version 6, as specified in 1568 RFC 1883, the octet string MUST contain exactly sixteen octets [RFC 1569 1883]. 1571 When the subjectAltName extension contains a domain name service 1572 label, the domain name MUST be stored in the dNSName (an IA5String). 1573 The name MUST be in the "preferred name syntax," as specified by RFC 1574 1034 [RFC 1034]. Note that while upper and lower case letters are 1575 allowed in domain names, no signifigance is attached to the case. In 1576 addition, while the string " " is a legal domain name, subjectAltName 1577 extensions with a dNSName " " are not permitted. Finally, the use of 1578 the DNS representation for Internet mail addresses (wpolk.nist.gov 1579 instead of wpolk@nist.gov) MUST NOT be used; such identities are to 1580 be encoded as rfc822Name. 1582 Note: work is currently underway to specify domain names in 1583 international character sets. This names will likely not be 1584 accomodated by IA5String. Once this work is complete, this profile 1585 will be revisited and the appropriate functionality will be added. 1587 When the subjectAltName extension contains a URI, the name MUST be 1588 stored in the uniformResourceIdentifier (an IA5String). The name 1589 MUST NOT be a relative URL, and it MUST follow the URL syntax and 1590 encoding rules specified in [RFC 1738]. The name MUST include both a 1591 scheme (e.g., "http" or "ftp") and a scheme-specific-part. The 1592 scheme-specific-part MUST include a fully qualified domain name or IP 1593 address as the host. 1595 As specified in [RFC 1738], the scheme name is not case-sensitive 1596 (e.g., "http" is equivalent to "HTTP"). The host part is also not 1597 case-sensitive, but other components of the scheme-specific-part may 1598 be case-sensitive. When comparing URIs, conforming implementations 1599 MUST compare the scheme and host without regard to case, but assume 1600 the remainder of the scheme-specific-part is case sensitive. 1602 When the subjectAltName extension contains a DN in the directoryName, 1603 the DN MUST be unique for each subject entity certified by the one CA 1604 as defined by the issuer name field. A CA MAY issue more than one 1605 certificate with the same DN to the same subject entity. 1607 The subjectAltName MAY carry additional name types through the use of 1608 the otherName field. The format and semantics of the name are 1609 indicated through the OBJECT IDENTIFIER in the type-id field. The 1610 name itself is conveyed as value field in otherName. For example, 1611 Kerberos [RFC 1510] format names can be encoded into the otherName, 1612 using the krb5PrincipalName OID and the KerberosName syntax as 1613 defined in [PKINIT]. 1615 Subject alternative names MAY be constrained in the same manner as 1616 subject distinguished names using the name constraints extension as 1617 described in section 4.2.1.11. 1619 If the subjectAltName extension is present, the sequence MUST contain 1620 at least one entry. Unlike the subject field, conforming CAs MUST 1621 NOT issue certificates with subjectAltNames containing empty 1622 GeneralName fields. For example, an rfc822Name is represented as an 1623 IA5String. While an empty string is a valid IA5String, such an 1624 rfc822Name is not permitted by this profile. The behavior of clients 1625 that encounter such a certificate when processing a certificication 1626 path is not defined by this profile. 1628 Finally, the semantics of subject alternative names that include 1629 wildcard characters (e.g., as a placeholder for a set of names) are 1630 not addressed by this specification. Applications with specific 1631 requirements MAY use such names, but they MUST define the semantics. 1633 id-ce-subjectAltName OBJECT IDENTIFIER ::= { id-ce 17 } 1635 SubjectAltName ::= GeneralNames 1637 GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName 1639 GeneralName ::= CHOICE { 1640 otherName [0] OtherName, 1641 rfc822Name [1] IA5String, 1642 dNSName [2] IA5String, 1643 x400Address [3] ORAddress, 1644 directoryName [4] Name, 1645 ediPartyName [5] EDIPartyName, 1646 uniformResourceIdentifier [6] IA5String, 1647 iPAddress [7] OCTET STRING, 1648 registeredID [8] OBJECT IDENTIFIER} 1650 OtherName ::= SEQUENCE { 1651 type-id OBJECT IDENTIFIER, 1652 value [0] EXPLICIT ANY DEFINED BY type-id } 1654 EDIPartyName ::= SEQUENCE { 1655 nameAssigner [0] DirectoryString OPTIONAL, 1656 partyName [1] DirectoryString } 1658 4.2.1.8 Issuer Alternative Names 1660 As with 4.2.1.7, this extension is used to associate Internet style 1661 identities with the certificate issuer. Issuer alternative names MUST 1662 be encoded as in 4.2.1.7. 1664 Where present, this extension SHOULD NOT be marked critical. 1666 id-ce-issuerAltName OBJECT IDENTIFIER ::= { id-ce 18 } 1668 IssuerAltName ::= GeneralNames 1670 4.2.1.9 Subject Directory Attributes 1672 The subject directory attributes extension is used to convey 1673 identification attributes (e.g., nationality) of the subject. The 1674 extension is defined as a sequence of one or more attributes. This 1675 extension MUST be non-critical. 1677 id-ce-subjectDirectoryAttributes OBJECT IDENTIFIER ::= { id-ce 9 } 1679 SubjectDirectoryAttributes ::= SEQUENCE SIZE (1..MAX) OF Attribute 1681 4.2.1.10 Basic Constraints 1683 The basic constraints extension identifies whether the subject of the 1684 certificate is a CA and the maximum depth of valid certification 1685 paths that include this certificate. 1687 The cA boolean indicates whether the certified public key belongs to 1688 a CA. If the cA boolean is not asserted, then the keyCertSign bit in 1689 the key usage extension MUST NOT be asserted. 1691 The pathLenConstraint field is meaningful only if the cA boolean is 1692 asserted and the key usage extension asserts the keyCertSign bit 1693 (section 4.2.1.3). In this case, it gives the maximum number of non- 1694 self-issued intermediate certificates that may follow this 1695 certificate in a valid certification path. A certificate is self- 1696 issued if the DNs that appear in the subject and issuer fields are 1697 identical and are not empty. (Note: The last certificate in the 1698 certification path is not an intermediate certificate, and is not 1699 included in this limit. Usually, the last certificate is an end 1700 entity certificate, but it can be a CA certificate.) A 1701 pathLenConstraint of zero indicates that only one more certificate 1702 may follow in a valid certification path. Where it appears, the 1703 pathLenConstraint field MUST be greater than or equal to zero. Where 1704 pathLenConstraint does not appear, no limit is imposed. 1706 This extension MUST appear as a critical extension in all CA 1707 certificates that contain public keys used to validate digital 1708 signatures on certificates. This extension MAY appear as a critical 1709 or non-critical extension in CA certificates that contain public keys 1710 used exclusively for purposes other than validating digital 1711 signatures on certificates. Such CA certificates include ones that 1712 contain public keys used exclusively for validating digital 1713 signatures on CRLs and ones that contain key management public keys 1714 used with certificate enrollment protocols. This extension MAY 1715 appear as a critical or non-critical extension in end entity 1716 certificates. 1718 CAs MUST NOT include the pathLenConstraint field unless the cA 1719 boolean is asserted and the key usage extension asserts the 1720 keyCertSign bit. 1722 id-ce-basicConstraints OBJECT IDENTIFIER ::= { id-ce 19 } 1724 BasicConstraints ::= SEQUENCE { 1725 cA BOOLEAN DEFAULT FALSE, 1726 pathLenConstraint INTEGER (0..MAX) OPTIONAL } 1728 4.2.1.11 Name Constraints 1730 The name constraints extension, which MUST be used only in a CA 1731 certificate, indicates a name space within which all subject names in 1732 subsequent certificates in a certification path MUST be located. 1733 Restrictions apply to the subject distinguished name and apply to 1734 subject alternative names. Restrictions apply only when the 1735 specified name form is present. If no name of the type is in the 1736 certificate, the certificate is acceptable. 1738 Name constraints are not applied to certificates whose issuer and 1739 subject are identical (unless the certificate is the final 1740 certificate in the path). (This could prevent CAs that use name 1741 constraints from employing self-issued certificates to implement key 1742 rollover.) 1744 Restrictions are defined in terms of permitted or excluded name 1745 subtrees. Any name matching a restriction in the excludedSubtrees 1746 field is invalid regardless of information appearing in the 1747 permittedSubtrees. This extension MUST be critical. 1749 Within this profile, the minimum and maximum fields are not used with 1750 any name forms, thus minimum is always zero, and maximum is always 1751 absent. 1753 For URIs, the constraint applies to the host part of the name. The 1754 constraint MAY specify a host or a domain. Examples would be 1755 "foo.bar.com"; and ".xyz.com". When the the constraint begins with 1756 a period, it MAY be expanded with one or more subdomains. That is, 1757 the constraint ".xyz.com" is satisfied by both abc.xyz.com and 1758 abc.def.xyz.com. However, the constraint ".xyz.com" is not satisfied 1759 by "xyz.com". When the constraint does not begin with a period, it 1760 specifies a host. 1762 A name constraint for Internet mail addresses MAY specify a 1763 particular mailbox, all addresses at a particular host, or all 1764 mailboxes in a domain. To indicate a particular mailbox, the 1765 constraint is the complete mail address. For example, "root@xyz.com" 1766 indicates the root mailbox on the host "xyz.com". To indicate all 1767 Internet mail addresses on a particular host, the constraint is 1768 specified as the host name. For example, the constraint "xyz.com" is 1769 satisfied by any mail address at the host "xyz.com". To specify any 1770 address within a domain, the constraint is specified with a leading 1771 period (as with URIs). For example, ".xyz.com" indicates all the 1772 Internet mail addresses in the domain "xyz.com", but not Internet 1773 mail addresses on the host "xyz.com". 1775 DNS name restrictions are expressed as foo.bar.com. Any DNS name that 1776 can be constructed by simply adding to the left hand side of the name 1777 satisfies the name constraint. For example, www.foo.bar.com would 1778 satisfy the constraint but foo1.bar.com would not. 1780 Legacy implementations exist where an RFC 822 name is embedded in the 1781 subject distinguished name in an attribute of type EmailAddress 1782 (section 4.1.2.6). When rfc822 names are constrained, but the 1783 certificate does not include a subject alternative name, the rfc822 1784 name constraint MUST be applied to the attribute of type EmailAddress 1785 in the subject distinguished name. The ASN.1 syntax for EmailAddress 1786 and the corresponding OID are supplied in Appendix A. 1788 Restrictions of the form directoryName MUST be applied to the subject 1789 field in the certificate and to the subjectAltName extensions of type 1790 directoryName. Restrictions of the form x400Address MUST be applied 1791 to subjectAltName extensions of type x400Address. 1793 When applying restrictions of the form directoryName, an 1794 implementation MUST compare DN attributes. At a minimum, 1795 implementations MUST perform the DN comparison rules specified in 1796 Section 4.1.2.4. CAs issuing certificates with a restriction of the 1797 form directoryName SHOULD NOT rely on implementation of the full ISO 1798 DN name comparison algorithm. This implies name restrictions MUST be 1799 stated identically to the encoding used in the subject field or 1800 subjectAltName extension. 1802 The syntax of iPAddress MUST be as described in section 4.2.1.7 with 1803 the following additions specifically for Name Constraints. For IPv4 1804 addresses, the ipAddress field of generalName MUST contain eight (8) 1805 octets, encoded in the style of RFC 1519 (CIDR) to represent an 1806 address range.[RFC 1519] For IPv6 addresses, the ipAddress field 1807 MUST contain 32 octets similarly encoded. For example, a name 1808 constraint for "class C" subnet 10.9.8.0 is represented as the octets 1809 0A 09 08 00 FF FF FF 00, representing the CIDR notation 1810 10.9.8.0/255.255.255.0. 1812 The syntax and semantics for name constraints for otherName, 1813 ediPartyName, and registeredID are not defined by this specification. 1815 id-ce-nameConstraints OBJECT IDENTIFIER ::= { id-ce 30 } 1817 NameConstraints ::= SEQUENCE { 1818 permittedSubtrees [0] GeneralSubtrees OPTIONAL, 1819 excludedSubtrees [1] GeneralSubtrees OPTIONAL } 1821 GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree 1823 GeneralSubtree ::= SEQUENCE { 1824 base GeneralName, 1825 minimum [0] BaseDistance DEFAULT 0, 1826 maximum [1] BaseDistance OPTIONAL } 1828 BaseDistance ::= INTEGER (0..MAX) 1830 4.2.1.12 Policy Constraints 1832 The policy constraints extension can be used in certificates issued 1833 to CAs. The policy constraints extension constrains path validation 1834 in two ways. It can be used to prohibit policy mapping or require 1835 that each certificate in a path contain an acceptable policy 1836 identifier. 1838 If the inhibitPolicyMapping field is present, the value indicates the 1839 number of additional certificates that may appear in the path before 1840 policy mapping is no longer permitted. For example, a value of one 1841 indicates that policy mapping may be processed in certificates issued 1842 by the subject of this certificate, but not in additional 1843 certificates in the path. 1845 If the requireExplicitPolicy field is present, subsequent 1846 certificates MUST include an acceptable policy identifier. The value 1847 of requireExplicitPolicy indicates the number of additional 1848 certificates that may appear in the path before an explicit policy is 1849 required. An acceptable policy identifier is the identifier of a 1850 policy required by the user of the certification path or the 1851 identifier of a policy which has been declared equivalent through 1852 policy mapping. 1854 Conforming CAs MUST NOT issue certificates where policy constraints 1855 is a empty sequence. That is, at least one of the 1856 inhibitPolicyMapping field or the requireExplicitPolicy field MUST be 1857 present. The behavior of clients that encounter a empty policy 1858 constraints field is not addressed in this profile. 1860 This extension MAY be critical or non-critical. 1862 id-ce-policyConstraints OBJECT IDENTIFIER ::= { id-ce 36 } 1864 PolicyConstraints ::= SEQUENCE { 1865 requireExplicitPolicy [0] SkipCerts OPTIONAL, 1866 inhibitPolicyMapping [1] SkipCerts OPTIONAL } 1868 SkipCerts ::= INTEGER (0..MAX) 1870 4.2.1.13 Extended key usage field 1872 This field indicates one or more purposes for which the certified 1873 public key may be used, in addition to or in place of the basic 1874 purposes indicated in the key usage extension field. In general, 1875 this extension will appear only in end entity certificates. This 1876 field is defined as follows: 1878 id-ce-extKeyUsage OBJECT IDENTIFIER ::= { id-ce 37 } 1880 ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId 1882 KeyPurposeId ::= OBJECT IDENTIFIER 1884 Key purposes may be defined by any organization with a need. Object 1885 identifiers used to identify key purposes MUST be assigned in 1886 accordance with IANA or ITU-T Recommendation X.660. 1888 This extension MAY, at the option of the certificate issuer, be 1889 either critical or non-critical. 1891 If the extension is flagged critical, then the certificate MUST only 1892 be used for one of the purposes indicated. If multiple purposes are 1893 indicated the application need not recognize all purposes indicated, 1894 as long as the intended purpose is present and recognized. 1896 If the extension is flagged non-critical, then it indicates the 1897 intended purpose or purposes of the key, and MAY be used in finding 1898 the correct key/certificate of an entity that has multiple 1899 keys/certificates. It is an advisory field and does not imply that 1900 usage of the key is restricted by the certification authority to the 1901 purpose indicated. Certificate using applications MAY nevertheless 1902 require that a particular purpose be indicated in order for the 1903 certificate to be acceptable to that application. 1905 If a certificate contains both a critical key usage field and a 1906 critical extended key usage field, then both fields MUST be processed 1907 independently and the certificate MUST only be used for a purpose 1908 consistent with both fields. If there is no purpose consistent with 1909 both fields, then the certificate MUST NOT be used for any purpose. 1911 The following key usage purposes are defined by this profile: 1913 id-kp OBJECT IDENTIFIER ::= { id-pkix 3 } 1915 id-kp-serverAuth OBJECT IDENTIFIER ::= { id-kp 1 } 1916 -- TLS WWW server authentication 1917 -- Key usage bits that may be consistent: digitalSignature, 1918 -- keyEncipherment or keyAgreement 1920 id-kp-clientAuth OBJECT IDENTIFIER ::= { id-kp 2 } 1921 -- TLS WWW client authentication 1922 -- Key usage bits that may be consistent: digitalSignature 1923 -- and/or keyAgreement 1925 id-kp-codeSigning OBJECT IDENTIFIER ::= { id-kp 3 } 1926 -- Signing of downloadable executable code 1927 -- Key usage bits that may be consistent: digitalSignature 1929 id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 } 1930 -- E-mail protection 1931 -- Key usage bits that may be consistent: digitalSignature, 1932 -- nonRepudiation, and/or (keyEncipherment or keyAgreement) 1934 id-kp-timeStamping OBJECT IDENTIFIER ::= { id-kp 8 } 1935 -- Binding the hash of an object to a time 1936 -- Key usage bits that may be consistent: digitalSignature 1937 -- and/or nonRepudiation 1938 id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 } 1939 -- Signing OCSP responses 1940 -- Key usage bits that may be consistent: digitalSignature 1941 -- and/or nonRepudiation 1943 4.2.1.14 CRL Distribution Points 1945 The CRL distribution points extension identifies how CRL information 1946 is obtained. The extension SHOULD be non-critical, but this profile 1947 RECOMMENDS support for this extension by CAs and applications. 1948 Further discussion of CRL management is contained in section 5. 1950 The cRLDistributionPoints extension is a SEQUENCE of 1951 DistributionPoint. A DistributionPoint consists of three fields, 1952 each of which is optional: distributionPoint, reasons, and cRLIssuer. 1953 While each of these fields is optional, a DistributionPoint MUST NOT 1954 consist of only the reasons field; either distributionPoint or 1955 cRLIssuer MUST be present. If the certificate issuer is not the CRL 1956 issuer, then the cRLIssuer field MUST be present and contain the Name 1957 of the CRL issuer. If the certificate issuer is also the CRL issuer, 1958 then the cRLIssuer field MUST be omitted and the distributionPoint 1959 field MUST be present. If the the distributionPoint field is 1960 omitted, cRLIssuer MUST be present and include a Name corresponding 1961 to an X.500 or LDAP directory entry where the CRL is located. 1963 When the distributionPoint field is present, it contains either a 1964 SEQUENCE of general names or a single value, nameRelativeToCRLIssuer. 1965 If the cRLDistributionPoints extension contains a general name of 1966 type URI, the following semantics MUST be assumed: the URI is a 1967 pointer to the current CRL for the associated reasons and will be 1968 issued by the associated cRLIssuer. The expected values for the URI 1969 are those defined in 4.2.1.7. Processing rules for other values are 1970 not defined by this specification. 1972 If the DistributionPointName contains multiple values, each name 1973 describes a different mechanism to obtain the same CRL. For example, 1974 the same CRL could be available for retrieval through both LDAP and 1975 HTTP. 1977 If the DistributionPointName contains the single value 1978 nameRelativeToCRLIssuer, the value provides a distinguished name 1979 fragment. The fragment is appended to the X.500 distinguished name 1980 of the CRL issuer to obtain the distribution point name. If the 1981 cRLIssuer field in the DistributionPoint is present, then the name 1982 fragment is appended to the distinguished name that it contains; 1983 otherwise, the name fragment is appended to the certificate issuer 1984 distinguished name. The DistributionPointName MUST NOT use the 1985 nameRealtiveToCRLIssuer alternative when cRLIssuer contains more than 1986 one distinguished name. 1988 If the DistributionPoint omits the reasons field, the CRL MUST 1989 include revocation information for all reasons. 1991 The cRLIssuer identifies the entity who signs and issues the CRL. If 1992 present, the cRLIssuer MUST contain at least one an X.500 1993 distinguished name (DN), and MAY also contain other name forms. 1994 Since the cRLIssuer is compared to the CRL issuer name, the X.501 1995 type Name MUST follow the encoding rules for the issuer name field in 1996 the certificate (section 4.1.2.4). 1998 id-ce-cRLDistributionPoints OBJECT IDENTIFIER ::= { id-ce 31 } 2000 CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint 2002 DistributionPoint ::= SEQUENCE { 2003 distributionPoint [0] DistributionPointName OPTIONAL, 2004 reasons [1] ReasonFlags OPTIONAL, 2005 cRLIssuer [2] GeneralNames OPTIONAL } 2007 DistributionPointName ::= CHOICE { 2008 fullName [0] GeneralNames, 2009 nameRelativeToCRLIssuer [1] RelativeDistinguishedName } 2011 ReasonFlags ::= BIT STRING { 2012 unused (0), 2013 keyCompromise (1), 2014 cACompromise (2), 2015 affiliationChanged (3), 2016 superseded (4), 2017 cessationOfOperation (5), 2018 certificateHold (6), 2019 privilegeWithdrawn (7), 2020 aACompromise (8) } 2022 4.2.1.15 Inhibit Any-Policy 2024 The inhibit any-policy extension can be used in certificates issued 2025 to CAs. The inhibit any-policy indicates that the special any-policy 2026 OID, with the value { 2 5 29 32 0 }, is not considered an explicit 2027 match for other certificate policies. The value indicates the number 2028 of additional certificates that may appear in the path before any- 2029 policy is no longer permitted. For example, a value of one indicates 2030 that any-policy may be processed in certificates issued by the 2031 subject of this certificate, but not in additional certificates in 2032 the path. 2034 This extension MUST be critical. 2036 id-ce-inhibitAnyPolicy OBJECT IDENTIFIER ::= { id-ce 54 } 2038 InhibitAnyPolicy ::= SkipCerts 2040 SkipCerts ::= INTEGER (0..MAX) 2042 4.2.1.16 Freshest CRL (a.k.a. Delta CRL Distribution Point) 2044 The freshest CRL extension identifies how delta CRL information is 2045 obtained. The extension MUST be non-critical. Further discussion of 2046 CRL management is contained in section 5. 2048 The same syntax is used for this extension and the 2049 cRLDistributionPoints extension, and is described in section 2050 4.2.1.14. The same conventions apply to both extensions. 2052 id-ce-freshestCRL OBJECT IDENTIFIER ::= { id-ce 46 } 2054 FreshestCRL ::= CRLDistributionPoints 2056 4.2.2 Private Internet Extensions 2058 This section defines two extensions for use in the Internet Public 2059 Key Infrastructure. These extensions may be used to direct 2060 applications to on-line information about the issuing CA or the 2061 subject. As the information may be available in multiple forms, each 2062 extension is a sequence of IA5String values, each of which represents 2063 a URI. The URI implicitly specifies the location and format of the 2064 information and the method for obtaining the information. 2066 An object identifier is defined for the private extension. The 2067 object identifier associated with the private extension is defined 2068 under the arc id-pe within the arc id-pkix. Any future extensions 2069 defined for the Internet PKI are also expected to be defined under 2070 the arc id-pe. 2072 id-pkix OBJECT IDENTIFIER ::= 2073 { iso(1) identified-organization(3) dod(6) internet(1) 2074 security(5) mechanisms(5) pkix(7) } 2076 id-pe OBJECT IDENTIFIER ::= { id-pkix 1 } 2078 4.2.2.1 Authority Information Access 2080 The authority information access extension indicates how to access CA 2081 information and services for the issuer of the certificate in which 2082 the extension appears. Information and services may include on-line 2083 validation services and CA policy data. (The location of CRLs is not 2084 specified in this extension; that information is provided by the 2085 cRLDistributionPoints extension.) This extension may be included in 2086 subject or CA certificates, and it MUST be non-critical. 2088 id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 } 2090 AuthorityInfoAccessSyntax ::= 2091 SEQUENCE SIZE (1..MAX) OF AccessDescription 2093 AccessDescription ::= SEQUENCE { 2094 accessMethod OBJECT IDENTIFIER, 2095 accessLocation GeneralName } 2097 id-ad OBJECT IDENTIFIER ::= { id-pkix 48 } 2099 id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 } 2101 Each entry in the sequence AuthorityInfoAccessSyntax describes the 2102 format and location of additional information provided by the CA who 2103 issued the certificate in which this extension appears. The type and 2104 format of the information is specified by the accessMethod field; the 2105 accessLocation field specifies the location of the information. The 2106 retrieval mechanism may be implied by the accessMethod or specified 2107 by accessLocation. 2109 This profile defines one OID for accessMethod. The id-ad-caIssuers 2110 OID is used when the additional information lists CAs that have 2111 issued certificates superior to the CA that issued the certificate 2112 containing this extension. The referenced CA Issuers description is 2113 intended to aid certificate users in the selection of a certification 2114 path that terminates at a point trusted by the certificate user. 2116 When id-ad-caIssuers appears as accessInfoType, the accessLocation 2117 field describes the referenced description server and the access 2118 protocol to obtain the referenced description. The accessLocation 2119 field is defined as a GeneralName, which can take several forms. 2120 Where the information is available via http, ftp, or ldap, 2121 accessLocation MUST be a uniformResourceIdentifier. Where the 2122 information is available via the directory access protocol (dap), 2123 accessLocation MUST be a directoryName. When the information is 2124 available via electronic mail, accessLocation MUST be an rfc822Name. 2125 The semantics of other name forms of accessLocation (when 2126 accessMethod is id-ad-caIssuers) are not defined by this 2127 specification. 2129 [RFC 2560] defines the access descriptor for the Online Certificate 2130 Status Protocol. When this access descriptor appears in the 2131 authority information access extension, this indicates the issuer 2132 provides revocation information for this certificate through the 2133 named OCSP service. Additional access descriptors may be defined in 2134 other PKIX specifications. 2136 4.2.2.2 Subject Information Access 2138 The subject information access extension indicates how to access 2139 information and services for the subject of the certificate in which 2140 the extension appears. When the subject is a CA, information and 2141 services may include certificate validation services and CA policy 2142 data. When the subject is an end entity, the information describes 2143 the type of services offered and how to access them. In this case, 2144 the contents of this extension are defined in the protocol 2145 specifications for the suported services. This extension may be 2146 included in subject or CA certificates, and it MUST be non-critical. 2148 id-pe-subjectInfoAccess OBJECT IDENTIFIER ::= { id-pe 11 } 2150 SubjectInfoAccessSyntax ::= 2151 SEQUENCE SIZE (1..MAX) OF AccessDescription 2153 AccessDescription ::= SEQUENCE { 2154 accessMethod OBJECT IDENTIFIER, 2155 accessLocation GeneralName } 2157 Each entry in the sequence SubjectInfoAccessSyntax describes the 2158 format and location of additional information provided by the subject 2159 of the certificate in which this extension appears. The type and 2160 format of the information is specified by the accessMethod field; the 2161 accessLocation field specifies the location of the information. The 2162 retrieval mechanism may be implied by the accessMethod or specified 2163 by accessLocation. 2165 This profile defines one access method to be used when the subject is 2166 a CA, and one access method to be used when the subject is an end 2167 entity. Additional access methods may be defined in the future in 2168 the protocol specifications for other services. 2170 The id-ad-caRepository OID is used when the subject is a CA, and 2171 publishes its certificates and CRLs (if issued) in a repository. The 2172 accessLocation field is defined as a GeneralName, which can take 2173 several forms. Where the information is available via http, ftp, or 2174 ldap, accessLocation MUST be a uniformResourceIdentifier. Where the 2175 information is available via the directory access protocol (dap), 2176 accessLocation MUST be a directoryName. When the information is 2177 available via electronic mail, accessLocation MUST be an rfc822Name. 2179 The semantics of other name forms of of accessLocation (when 2180 accessMethod is id-ad-caRepository) are not defined by this 2181 specification. 2183 The id-ad-timeStamping OID is used when the subject offers 2184 timestamping services using the Time Stamp Protocol defined in 2185 [PKIXTSA]. Where the timestamping services are available via http or 2186 ftp, accessLocation MUST be a uniformResourceIdentifier. Where the 2187 timestamping services are available via electronic mail, 2188 accessLocation MUST be an rfc822Name. Where timestamping services 2189 are available using TCP/IP, the dNSName or ipAddress name forms may 2190 be used. The semantics of other name forms of accessLocation (when 2191 accessMethod is id-ad-timeStamping) are not defined by this 2192 specification. 2194 Additional access descriptors may be defined in other PKIX 2195 specifications. 2197 id-ad OBJECT IDENTIFIER ::= { id-pkix 48 } 2199 id-ad-caRepository OBJECT IDENTIFIER ::= { id-ad 5 } 2201 id-ad-timeStamping OBJECT IDENTIFIER ::= { id-ad 3 } 2203 5 CRL and CRL Extensions Profile 2205 As discussed above, one goal of this X.509 v2 CRL profile is to 2206 foster the creation of an interoperable and reusable Internet PKI. 2207 To achieve this goal, guidelines for the use of extensions are 2208 specified, and some assumptions are made about the nature of 2209 information included in the CRL. 2211 CRLs may be used in a wide range of applications and environments 2212 covering a broad spectrum of interoperability goals and an even 2213 broader spectrum of operational and assurance requirements. This 2214 profile establishes a common baseline for generic applications 2215 requiring broad interoperability. The profile defines a set of 2216 information that can be expected in every CRL. Also, the profile 2217 defines common locations within the CRL for frequently used 2218 attributes as well as common representations for these attributes. 2220 CRL issuers issue CRLs. In general, the CRL issuer is the CA. CAs 2221 publish CRLs to provide status information about the certificates 2222 they issued. However, a CA may delegate this responsibility to 2223 another trusted authority. Whenever the CRL issuer is not the CA 2224 that issued the certificates, the CRL is referred to as an indirect 2225 CRL. 2227 Each CRL has a particular scope. The CRL scope is the set of 2228 certificates that could appear on a given CRL. For example, the 2229 scope could be "all certificates issued by CA X", "all CA 2230 certificates issued by CA X", "all certificates issued by CA X that 2231 have been revoked for reasons of key compromise and CA compromise", 2232 or could be a set of certificates based on arbitrary local 2233 information, such as "all certificates issued to the NIST employees 2234 located in Boulder". 2236 A complete CRL lists all unexpired certificates, within its scope, 2237 that have been revoked for one of the revocation reasons covered by 2238 the CRL scope. The CRL issuer MAY also generate delta CRLs. A delta 2239 CRL only lists those certificates, within its scope, whose revocation 2240 status has changed since the issuance of a referenced complete CRL. 2241 The referenced complete CRL is referred to as a base CRL. The scope 2242 of a delta CRL MUST be the same as the base CRL that it references. 2244 This profile does not define any private Internet CRL extensions or 2245 CRL entry extensions. 2247 Environments with additional or special purpose requirements may 2248 build on this profile or may replace it. 2250 Conforming CAs are not required to issue CRLs if other revocation or 2251 certificate status mechanisms are provided. Conforming CAs that 2252 issue CRLs MUST issue version 2 CRLs, include the date by which the 2253 next CRL will be issued in the nextUpdate field (section 5.1.2.5), 2254 include the CRL number extension (section 5.2.3), and include the 2255 authority key identifier extension (section 5.2.1). Conforming 2256 applications that support CRLs are required to process both version 1 2257 and version 2 complete CRLs that provide revocation information for 2258 all certificates issued by one CA. Conforming applications are not 2259 required to support processing of delta CRLs, indirect CRLs, or CRLs 2260 with a scope other than all certificates issued by the CA. 2262 5.1 CRL Fields 2264 The X.509 v2 CRL syntax is as follows. For signature calculation, 2265 the data that is to be signed is ASN.1 DER encoded. ASN.1 DER 2266 encoding is a tag, length, value encoding system for each element. 2268 CertificateList ::= SEQUENCE { 2269 tbsCertList TBSCertList, 2270 signatureAlgorithm AlgorithmIdentifier, 2271 signatureValue BIT STRING } 2273 TBSCertList ::= SEQUENCE { 2274 version Version OPTIONAL, 2275 -- if present, MUST be v2 2276 signature AlgorithmIdentifier, 2277 issuer Name, 2278 thisUpdate Time, 2279 nextUpdate Time OPTIONAL, 2280 revokedCertificates SEQUENCE OF SEQUENCE { 2281 userCertificate CertificateSerialNumber, 2282 revocationDate Time, 2283 crlEntryExtensions Extensions OPTIONAL 2284 -- if present, MUST be v2 2285 } OPTIONAL, 2286 crlExtensions [0] EXPLICIT Extensions OPTIONAL 2287 -- if present, MUST be v2 2288 } 2290 -- Version, Time, CertificateSerialNumber, and Extensions 2291 -- are all defined in the ASN.1 in section 4.1 2293 -- AlgorithmIdentifier is defined in section 4.1.1.2 2295 The following items describe the use of the X.509 v2 CRL in the 2296 Internet PKI. 2298 5.1.1 CertificateList Fields 2300 The CertificateList is a SEQUENCE of three required fields. The 2301 fields are described in detail in the following subsections. 2303 5.1.1.1 tbsCertList 2305 The first field in the sequence is the tbsCertList. This field is 2306 itself a sequence containing the name of the issuer, issue date, 2307 issue date of the next list, the optional list of revoked 2308 certificates, and optional CRL extensions. When there are no revoked 2309 certificates, the revoked certificates list is absent. When one or 2310 more certificates are revoked, each entry on the revoked certificate 2311 list is defined by a sequence of user certificate serial number, 2312 revocation date, and optional CRL entry extensions. 2314 5.1.1.2 signatureAlgorithm 2316 The signatureAlgorithm field contains the algorithm identifier for 2317 the algorithm used by the CRL issuer to sign the CertificateList. 2318 The field is of type AlgorithmIdentifier, which is defined in section 2319 4.1.1.2. [PKIXALGS] lists the supported algorithms for this 2320 specification. Conforming CAs MUST use the algorithm identifiers 2321 presented in [PKIXALGS] when signing with a supported signature 2322 algorithm. 2324 This field MUST contain the same algorithm identifier as the 2325 signature field in the sequence tbsCertList (section 5.1.2.2). 2327 5.1.1.3 signatureValue 2329 The signatureValue field contains a digital signature computed upon 2330 the ASN.1 DER encoded tbsCertList. The ASN.1 DER encoded tbsCertList 2331 is used as the input to the signature function. This signature value 2332 is then ASN.1 encoded as a BIT STRING and included in the CRL's 2333 signatureValue field. The details of this process are specified for 2334 each of the supported algorithms in [PKIXALGS]. 2336 CAs that are also CRL issuers MAY use one private key to digitally 2337 sign certificates and CRLs, or MAY use separate private keys to 2338 digitally sign certificates and CRLs. When separate private keys are 2339 employed, each of the public keys associated with these private keys 2340 is placed in a separate certificate, one with the keyCertSign bit set 2341 in the key usage extension, and one with the cRLSign bit set in the 2342 key usage extension (section 4.2.1.3). When separate private keys 2343 are employed, certificates issued by the CA contain one authority key 2344 identifier, and the corresponding CRLs contain a different authority 2345 key identifier. The use of separate CA certificates for validation 2346 of certificate signatures and CRL signatures can offer improved 2347 security characteristics; however, it imposes a burden on 2348 applications, and it might limit interoperability. Many applications 2349 construct a certification path, and then validate the certification 2350 path (section 6). CRL checking in turn requires a separate 2351 certification path to be constructed and validated for the CA's CRL 2352 signature validation certificate. Applications that perform CRL 2353 checking MUST support certification path validation when certificates 2354 and CRLs are digitally signed with the same CA private key. These 2355 applications SHOULD support certification path validation when 2356 certificates and CRLs are digitally signed with different CA private 2357 keys. 2359 5.1.2 Certificate List "To Be Signed" 2361 The certificate list to be signed, or TBSCertList, is a SEQUENCE of 2362 required and optional fields. The required fields identify the CRL 2363 issuer, the algorithm used to sign the CRL, the date and time the CRL 2364 was issued, and the date and time by which the CRL issuer will issue 2365 the next CRL. 2367 Optional fields include lists of revoked certificates and CRL 2368 extensions. The revoked certificate list is optional to support the 2369 case where a CA has not revoked any unexpired certificates that it 2370 has issued. The profile requires conforming CRL issuers to use the 2371 CRL Number CRL extension in all CRLs issued. 2373 5.1.2.1 Version 2375 This optional field describes the version of the encoded CRL. When 2376 extensions are used, as required by this profile, this field MUST be 2377 present and MUST specify version 2 (the integer value is 1). 2379 5.1.2.2 Signature 2381 This field contains the algorithm identifier for the algorithm used 2382 to sign the CRL. [PKIXALGS] lists OIDs for the most popular 2383 signature algorithms used in the Internet PKI. 2385 This field MUST contain the same algorithm identifier as the 2386 signatureAlgorithm field in the sequence CertificateList (section 2387 5.1.1.2). 2389 5.1.2.3 Issuer Name 2391 The issuer name identifies the entity who has signed and issued the 2392 CRL. The issuer identity is carried in the issuer name field. 2393 Alternative name forms may also appear in the issuerAltName extension 2394 (section 5.2.2). The issuer name field MUST contain an X.500 2395 distinguished name (DN). The issuer name field is defined as the 2396 X.501 type Name, and MUST follow the encoding rules for the issuer 2397 name field in the certificate (section 4.1.2.4). 2399 5.1.2.4 This Update 2401 This field indicates the issue date of this CRL. ThisUpdate may be 2402 encoded as UTCTime or GeneralizedTime. 2404 CRL issuers conforming to this profile MUST encode thisUpdate as 2405 UTCTime for dates through the year 2049. CRL issuers conforming to 2406 this profile MUST encode thisUpdate as GeneralizedTime for dates in 2407 the year 2050 or later. 2409 Where encoded as UTCTime, thisUpdate MUST be specified and 2410 interpreted as defined in section 4.1.2.5.1. Where encoded as 2411 GeneralizedTime, thisUpdate MUST be specified and interpreted as 2412 defined in section 4.1.2.5.2. 2414 5.1.2.5 Next Update 2416 This field indicates the date by which the next CRL will be issued. 2417 The next CRL could be issued before the indicated date, but it will 2418 not be issued any later than the indicated date. CRL issuers SHOULD 2419 issue CRLs with a nextUpdate time equal to or later than all previous 2420 CRLs. nextUpdate may be encoded as UTCTime or GeneralizedTime. 2422 This profile requires inclusion of nextUpdate in all CRLs issued by 2423 conforming CRL issuers. Note that the ASN.1 syntax of TBSCertList 2424 describes this field as OPTIONAL, which is consistent with the ASN.1 2425 structure defined in [X.509]. The behavior of clients processing CRLs 2426 which omit nextUpdate is not specified by this profile. 2428 CRL issuers conforming to this profile MUST encode nextUpdate as 2429 UTCTime for dates through the year 2049. CRL issuers conforming to 2430 this profile MUST encode nextUpdate as GeneralizedTime for dates in 2431 the year 2050 or later. 2433 Where encoded as UTCTime, nextUpdate MUST be specified and 2434 interpreted as defined in section 4.1.2.5.1. Where encoded as 2435 GeneralizedTime, nextUpdate MUST be specified and interpreted as 2436 defined in section 4.1.2.5.2. 2438 5.1.2.6 Revoked Certificates 2440 When there are no revoked certificates, the revoked certificates list 2441 is absent. Otherwise, revoked certificates are listed by their 2442 serial numbers. Certificates revoked by the CA are uniquely 2443 identified by the certificate serial number. The date on which the 2444 revocation occurred is specified. The time for revocationDate MUST 2445 be expressed as described in section 5.1.2.4. Additional information 2446 may be supplied in CRL entry extensions; CRL entry extensions are 2447 discussed in section 5.3. 2449 5.1.2.7 Extensions 2451 This field may only appear if the version is 2 (section 5.1.2.1). If 2452 present, this field is a SEQUENCE of one or more CRL extensions. CRL 2453 extensions are discussed in section 5.2. 2455 5.2 CRL Extensions 2457 The extensions defined by ANSI X9 and ISO/IEC/ITU for X.509 v2 CRLs 2458 [X.509] [X9.55] provide methods for associating additional attributes 2459 with CRLs. The X.509 v2 CRL format also allows communities to define 2460 private extensions to carry information unique to those communities. 2461 Each extension in a CRL may be designated as critical or non- 2462 critical. A CRL validation MUST fail if it encounters a critical 2463 extension which it does not know how to process. However, an 2464 unrecognized non-critical extension may be ignored. The following 2465 subsections present those extensions used within Internet CRLs. 2466 Communities MAY elect to include extensions in CRLs which are not 2467 defined in this specification. However, caution SHOULD be exercised 2468 in adopting any critical extensions in CRLs which might be used in a 2469 general context. 2471 Conforming CRL issuers are required to include the authority key 2472 identifier (section 5.2.1) and the CRL number (section 5.2.3) 2473 extensions in all CRLs issued. 2475 5.2.1 Authority Key Identifier 2477 The authority key identifier extension provides a means of 2478 identifying the public key corresponding to the private key used to 2479 sign a CRL. The identification can be based on either the key 2480 identifier (the subject key identifier in the CRL signer's 2481 certificate) or on the issuer name and serial number. This extension 2482 is especially useful where an issuer has more than one signing key, 2483 either due to multiple concurrent key pairs or due to changeover. 2485 Conforming CRL issuers MUST use the key identifier method, and MUST 2486 include this extension in all CRLs issued. 2488 The syntax for this CRL extension is defined in section 4.2.1.1. 2490 5.2.2 Issuer Alternative Name 2492 The issuer alternative names extension allows additional identities 2493 to be associated with the issuer of the CRL. Defined options include 2494 an rfc822 name (electronic mail address), a DNS name, an IP address, 2495 and a URI. Multiple instances of a name and multiple name forms may 2496 be included. Whenever such identities are used, the issuer 2497 alternative name extension MUST be used; however, a DNS name MAY be 2498 represented in the issuer field using the domainComponent attribute 2499 as described in section 4.1.2.4. 2501 The issuerAltName extension SHOULD NOT be marked critical. 2503 The OID and syntax for this CRL extension are defined in section 2504 4.2.1.8. 2506 5.2.3 CRL Number 2508 The CRL number is a non-critical CRL extension which conveys a 2509 monotonically increasing sequence number for a given CRL scope and 2510 CRL issuer. This extension allows users to easily determine when a 2511 particular CRL supersedes another CRL. CRL numbers also support the 2512 identification of complementary complete CRLs and delta CRLs. CRL 2513 issuers conforming to this profile MUST include this extension in all 2514 CRLs. 2516 If a CRL issuer generates delta CRLs in addition to complete CRLs for 2517 a given scope, the complete CRLs and delta CRLs MUST share one 2518 numbering sequence. If a delta CRL and a complete CRL that cover the 2519 same scope are issued at the same time, they MUST have the same CRL 2520 number and provide the same revocation information. That is, the 2521 combination of the delta CRL and an acceptable complete CRL MUST 2522 provide the same revocation information as the simultaneously issued 2523 complete CRL. 2525 If a CRL issuer generates two CRLs (two complete CRLs, two delta 2526 CRLs, or a complete CRL and a delta CRL) for the same scope at 2527 different times, the two CRLs MUST NOT have the same CRL number. 2528 That is, if the this update field (section 5.1.2.4) in the two CRLs 2529 are not identical, the CRL numbers MUST be different. 2531 id-ce-cRLNumber OBJECT IDENTIFIER ::= { id-ce 20 } 2533 CRLNumber ::= INTEGER (0..MAX) 2535 5.2.4 Delta CRL Indicator 2537 The delta CRL indicator is a critical CRL extension that identifies a 2538 CRL as being a delta CRL. Delta CRLs contain updates to revocation 2539 information previously distributed, rather than all the information 2540 that would appear in a complete CRL. The use of delta CRLs can 2541 significantly reduce network load and processing time in some 2542 environments. Delta CRLs are generally smaller than the CRLs they 2543 update, so applications that obtain delta CRLs consume less network 2544 bandwidth than applications that obtain the corresponding complete 2545 CRLs. Applications which store revocation information in a format 2546 other than the CRL structure can add new revocation information to 2547 the local database without reprocessing information. 2549 The delta CRL indicator extension contains the single value of type 2550 BaseCRLNumber. The CRL number identifies the CRL, complete for a 2551 given scope, that was used as the starting point in the generation of 2552 this delta CRL. A conforming CRL issuer MUST publish the referenced 2553 base CRL as a complete CRL. The delta CRL contains all updates to 2554 the revocation status for that same scope. The combination of a 2555 delta CRL plus the referenced base CRL is equivalent to a complete 2556 CRL, for the applicable scope, at the time of publication of the 2557 delta CRL. 2559 When a conforming CRL issuer generates a delta CRL, the delta CRL 2560 MUST include a critical delta CRL indicator extension. 2562 When a delta CRL is issued, it MUST cover the same set of reasons and 2563 the same set of certificates that were covered by the base CRL it 2564 references. That is, the scope of the delta CRL MUST be the same as 2565 the scope of the complete CRL referenced as the base. The referenced 2566 base CRL and the delta CRL MUST omit the issuing distribution point 2567 extension or contain identical issuing distribution point extensions. 2568 Further, the CRL issuer MUST use the same private key to sign the 2569 delta CRL and any complete CRL that it can be used to update. 2571 An application that supports delta CRLs can construct a CRL that is 2572 complete for a given scope by combining a delta CRL for that scope 2573 with either an issued CRL that is complete for that scope or a 2574 locally constructed CRL that is complete for that scope. 2576 When a delta CRL is combined with a complete CRL or a locally 2577 constructed CRL, the resulting locally constructed CRL has the CRL 2578 number specified in the CRL number extension found in the delta CRL 2579 used in its construction. In addition, the resulting locally 2580 constructed CRL has the thisUpdate and nextUpdate times specified in 2581 the corresponding fields of the delta CRL used in its construction. 2582 In addition, the locally constructed CRL inherits the issuing 2583 distribution point from the delta CRL. 2585 A complete CRL and a delta CRL MAY be combined if the following four 2586 conditions are satisfied: 2588 (a) The complete CRL and delta CRL have the same issuer. 2590 (b) The complete CRL and delta CRL have the same scope. The two 2591 CRLs have the same scope if either of the following conditions are 2592 met: 2594 (1) The issuingDistributionPoint extension is omitted from 2595 both the complete CRL and the delta CRL. 2597 (2) The issuingDistributionPoint extension is present in both 2598 the complete CRL and the delta CRL, and the values for each of 2599 the fields in the extensions are the same in both CRLs. 2601 (c) The CRL number of the complete CRL is equal to or greater 2602 than the BaseCRLNumber specified in the delta CRL. That is, the 2603 complete CRL contains (at a minimum) all the revocation 2604 information held by the referenced base CRL. 2606 (d) The CRL number of the complete CRL is less than the CRL 2607 number of the delta CRL. That is, the delta CRL follows the 2608 complete CRL in the numbering sequence. 2610 CRL issuers MUST ensure that the combination of a delta CRL and any 2611 appropriate complete CRL accurately reflects the current revocation 2612 status. The CRL issuer MUST include an entry in the delta CRL for 2613 each certificate within the scope of the delta CRL whose status has 2614 changed since the generation of the referenced base CRL: 2616 (a) If the certificate is revoked for a reason included in the 2617 scope of the CRL, list the certificate as revoked. 2619 (b) If the certificate is valid and was listed on the referenced 2620 base CRL or any subsequent CRL with reason code certificateHold, 2621 and the reason code certificateHold is included in the scope of 2622 the CRL, list the certificate with the reason code removeFromCRL. 2624 (c) If the certificate is revoked for a reason outside the scope 2625 of the CRL, but the certificate was listed on the referenced base 2626 CRL or any subsequent CRL with a reason code included in the scope 2627 of this CRL, list the certificate as revoked but omit the reason 2628 code. 2630 (d) If the certificate is revoked for a reason outside the scope 2631 of the CRL and the certificate was neither listed on the 2632 referenced base CRL nor any subsequent CRL with a reason code 2633 included in the scope of this CRL, do not list the certificate on 2634 this CRL. 2636 The status of a certificate is considered to have changed if it is 2637 revoked, placed on hold, released from hold, or if its revocation 2638 reason changes. 2640 It is appropriate to list a certificate with reason code 2641 removeFromCRL on a delta CRL even if the certificate was not on hold 2642 in the referenced base CRL. If the certificate was placed on hold in 2643 any CRL issued after the base but before this delta CRL and then 2644 released from hold, it MUST be listed on the delta CRL with 2645 revocation reason removeFromCRL. 2647 A CRL issuer MAY optionally list a certificate on a delta CRL with 2648 reason code removeFromCRL if the notAfter time specified in the 2649 certificate precedes the thisUpdate time specified in the delta CRL 2650 and the certificate was listed on the referenced base CRL or in any 2651 CRL issued after the base but before this delta CRL. 2653 If a certificate revocation notice first appears on a delta CRL, then 2654 it is possible for the certificate validity period to expire before 2655 the next complete CRL for the same scope is issued. In this case, 2656 the revocation notice MUST be included in all subsequent delta CRLs 2657 until the revocation notice is included on at least one explicitly 2658 issued complete CRL for this scope. 2660 An application that supports delta CRLs MUST be able to construct a 2661 current complete CRL by combining a previously issued complete CRL 2662 and the most current delta CRL. An application that supports delta 2663 CRLs MAY also be able to construct a current complete CRL by 2664 combining a previously locally constructed complete CRL and the 2665 current delta CRL. A delta CRL is considered to be the current one 2666 if the current time is between the times contained in the thisUpdate 2667 and nextUpdate fields. Under some circumstances, the CRL issuer may 2668 publish one or more delta CRLs before indicated by the nextUpdate 2669 field. If more than one current delta CRL for a given scope is 2670 encountered, the application SHOULD consider the one with the latest 2671 value in thisUpdate to be the most current one. 2673 id-ce-deltaCRLIndicator OBJECT IDENTIFIER ::= { id-ce 27 } 2675 BaseCRLNumber ::= CRLNumber 2677 5.2.5 Issuing Distribution Point 2679 The issuing distribution point is a critical CRL extension that 2680 identifies the CRL distribution point and scope for a particular CRL, 2681 and it indicates whether the CRL covers revocation for end entity 2682 certificates only, CA certificates only, attribute certificates 2683 only, or a limited set of reason codes. Although the extension is 2684 critical, conforming implementations are not required to support this 2685 extension. 2687 The CRL is signed using the CRL issuer's private key. CRL 2688 Distribution Points do not have their own key pairs. If the CRL is 2689 stored in the X.500 Directory, it is stored in the Directory entry 2690 corresponding to the CRL distribution point, which may be different 2691 than the Directory entry of the CRL issuer. 2693 The reason codes associated with a distribution point MUST be 2694 specified in onlySomeReasons. If onlySomeReasons does not appear, 2695 the distribution point MUST contain revocations for all reason codes. 2696 CAs may use CRL distribution points to partition the CRL on the basis 2697 of compromise and routine revocation. In this case, the revocations 2698 with reason code keyCompromise (1), cACompromise (2), and 2699 aACompromise (8) appear in one distribution point, and the 2700 revocations with other reason codes appear in another distribution 2701 point. 2703 If the distributionPoint field is present and contains a URI, the 2704 following semantics MUST be assumed: the object is a pointer to the 2705 most current CRL issued by this CRL issuer. The URI schemes ftp, 2706 http, mailto [RFC1738] and ldap [RFC1778] are defined for this 2707 purpose. The URI MUST be an absolute pathname, not a relative 2708 pathname, and MUST specify the host. 2710 If the distributionPoint field is absent, the CRL MUST contain 2711 entries for all revoked unexpired certificates issued by the CRL 2712 issuer, if any, within the scope of the CRL. 2714 The CRL issuer MUST assert the indirectCRL boolean, if the scope of 2715 the CRL includes certificates issued by authorities other than the 2716 CRL issuer. The authority responsible for each entry is indicated by 2717 the certificate issuer CRL entry extension (section 5.3.4). 2719 id-ce-issuingDistributionPoint OBJECT IDENTIFIER ::= { id-ce 28 } 2721 issuingDistributionPoint ::= SEQUENCE { 2722 distributionPoint [0] DistributionPointName OPTIONAL, 2723 onlyContainsUserCerts [1] BOOLEAN DEFAULT FALSE, 2724 onlyContainsCACerts [2] BOOLEAN DEFAULT FALSE, 2725 onlySomeReasons [3] ReasonFlags OPTIONAL, 2726 indirectCRL [4] BOOLEAN DEFAULT FALSE, 2727 onlyContainsAttributeCerts [5] BOOLEAN DEFAULT FALSE } 2729 5.2.6 Freshest CRL (a.k.a. Delta CRL Distribution Point) 2731 The freshest CRL extension identifies how delta CRL information for 2732 this complete CRL is obtained. The extension MUST be non-critical. 2733 This extension MUST NOT appear in delta CRLs. 2735 The same syntax is used for this extension as the 2736 cRLDistributionPoints certificate extension, and is described in 2737 section 4.2.1.14. However, only the distribution point field is 2738 meaningful in this context. The reasons and CRLIssuer fields MUST be 2739 omitted from this CRL extension. 2741 Each distribution point name provides the location at which a delta 2742 CRL for this complete CRL can be found. The scope of these delta 2743 CRLs MUST be the same as the scope of this complete CRL. The 2744 contents of this CRL extension are only used to locate delta CRLs; 2745 the contents are not used to validate the CRL or the referenced delta 2746 CRLs. The encoding conventions defined for distribution points in 2747 section 4.2.1.14 apply to this extension. 2749 id-ce-freshestCRL OBJECT IDENTIFIER ::= { id-ce 46 } 2751 FreshestCRL ::= CRLDistributionPoints 2753 5.3 CRL Entry Extensions 2755 The CRL entry extensions already defined by ANSI X9 and ISO/IEC/ITU 2756 for X.509 v2 CRLs provide methods for associating additional 2757 attributes with CRL entries [X.509] [X9.55]. The X.509 v2 CRL format 2758 also allows communities to define private CRL entry extensions to 2759 carry information unique to those communities. Each extension in a 2760 CRL entry may be designated as critical or non-critical. A CRL 2761 validation MUST fail if it encounters a critical CRL entry extension 2762 which it does not know how to process. However, an unrecognized non- 2763 critical CRL entry extension may be ignored. The following 2764 subsections present recommended extensions used within Internet CRL 2765 entries and standard locations for information. Communities MAY 2766 elect to use additional CRL entry extensions; however, caution SHOULD 2767 be exercised in adopting any critical extensions in CRL entries which 2768 might be used in a general context. 2770 All CRL entry extensions used in this specification are non-critical. 2771 Support for these extensions is optional for conforming CRL issuers 2772 and applications. However, CRL issuers SHOULD include reason codes 2773 (section 5.3.1) and invalidity dates (section 5.3.3) whenever this 2774 information is available. 2776 5.3.1 Reason Code 2778 The reasonCode is a non-critical CRL entry extension that identifies 2779 the reason for the certificate revocation. CRL issuers are strongly 2780 encouraged to include meaningful reason codes in CRL entries; 2781 however, the reason code CRL entry extension SHOULD be absent instead 2782 of using the unspecified (0) reasonCode value. 2784 id-ce-cRLReason OBJECT IDENTIFIER ::= { id-ce 21 } 2786 -- reasonCode ::= { CRLReason } 2788 CRLReason ::= ENUMERATED { 2789 unspecified (0), 2790 keyCompromise (1), 2791 cACompromise (2), 2792 affiliationChanged (3), 2793 superseded (4), 2794 cessationOfOperation (5), 2795 certificateHold (6), 2796 removeFromCRL (8), 2797 privilegeWithdrawn (9), 2798 aACompromise (10) } 2800 5.3.2 Hold Instruction Code 2802 The hold instruction code is a non-critical CRL entry extension that 2803 provides a registered instruction identifier which indicates the 2804 action to be taken after encountering a certificate that has been 2805 placed on hold. 2807 id-ce-holdInstructionCode OBJECT IDENTIFIER ::= { id-ce 23 } 2808 holdInstructionCode ::= OBJECT IDENTIFIER 2810 The following instruction codes have been defined. Conforming 2811 applications that process this extension MUST recognize the following 2812 instruction codes. 2814 holdInstruction OBJECT IDENTIFIER ::= 2815 { iso(1) member-body(2) us(840) x9-57(10040) 2 } 2817 id-holdinstruction-none OBJECT IDENTIFIER ::= {holdInstruction 1} 2818 id-holdinstruction-callissuer 2819 OBJECT IDENTIFIER ::= {holdInstruction 2} 2820 id-holdinstruction-reject OBJECT IDENTIFIER ::= {holdInstruction 3} 2822 Conforming applications which encounter an id-holdinstruction- 2823 callissuer MUST call the certificate issuer or reject the 2824 certificate. Conforming applications which encounter an id- 2825 holdinstruction-reject MUST reject the certificate. The hold 2826 instruction id-holdinstruction-none is semantically equivalent to the 2827 absence of a holdInstructionCode, and its use is strongly deprecated 2828 for the Internet PKI. 2830 5.3.3 Invalidity Date 2832 The invalidity date is a non-critical CRL entry extension that 2833 provides the date on which it is known or suspected that the private 2834 key was compromised or that the certificate otherwise became invalid. 2835 This date may be earlier than the revocation date in the CRL entry, 2836 which is the date at which the CA processed the revocation. When a 2837 revocation is first posted by a CRL issuer in a CRL, the invalidity 2838 date may precede the date of issue of earlier CRLs, but the 2839 revocation date SHOULD NOT precede the date of issue of earlier CRLs. 2840 Whenever this information is available, CRL issuers are strongly 2841 encouraged to share it with CRL users. 2843 The GeneralizedTime values included in this field MUST be expressed 2844 in Greenwich Mean Time (Zulu), and MUST be specified and interpreted 2845 as defined in section 4.1.2.5.2. 2847 id-ce-invalidityDate OBJECT IDENTIFIER ::= { id-ce 24 } 2849 invalidityDate ::= GeneralizedTime 2851 5.3.4 Certificate Issuer 2853 This CRL entry extension identifies the certificate issuer associated 2854 with an entry in an indirect CRL, that is, a CRL that has the 2855 indirectCRL indicator set in its issuing distribution point 2856 extension. If this extension is not present on the first entry in an 2857 indirect CRL, the certificate issuer defaults to the CRL issuer. On 2858 subsequent entries in an indirect CRL, if this extension is not 2859 present, the certificate issuer for the entry is the same as that for 2860 the preceding entry. This field is defined as follows: 2862 id-ce-certificateIssuer OBJECT IDENTIFIER ::= { id-ce 29 } 2864 certificateIssuer ::= GeneralNames 2866 If used by conforming CRL issuers, this extension MUST always be 2867 critical. If an implementation ignored this extension it could not 2868 correctly attribute CRL entries to certificates. This specification 2869 RECOMMENDS that implementations recognize this extension. 2871 6 Certification Path Validation 2873 Certification path validation procedures for the Internet PKI are 2874 based on the algorithm supplied in [X.509]. Certification path 2875 processing verifies the binding between the subject distinguished 2876 name and/or subject alternative name and subject public key. The 2877 binding is limited by constraints which are specified in the 2878 certificates which comprise the path and inputs which are specified 2879 by the relying party. The basic constraints and policy constraints 2880 extensions allow the certification path processing logic to automate 2881 the decision making process. 2883 This section describes an algorithm for validating certification 2884 paths. Conforming implementations of this specification are not 2885 required to implement this algorithm, but MUST provide functionality 2886 equivalent to the external behavior resulting from this procedure. 2887 Any algorithm may be used by a particular implementation so long as 2888 it derives the correct result. 2890 In section 6.1, the text describes basic path validation. Valid 2891 paths begin with certificates issued by a "most-trusted CA". The 2892 algorithm requires the public key of the CA, the CA's name, and any 2893 constraints upon the set of paths which may be validated using this 2894 key. 2896 The selection of a "most-trusted CA" is a matter of policy: it could 2897 be the top CA in a hierarchical PKI; the CA that issued the 2898 verifier's own certificate(s); or any other CA in a network PKI. The 2899 path validation procedure is the same regardless of the choice of 2900 "most-trusted CA." In addition, different applications may rely on 2901 different "most-trusted CA", or may accept paths that begin with any 2902 of a set of "most-trusted CAs." 2903 Section 6.2 describes methods for using the path validation algorithm 2904 in specific implementations. Two specific cases are discussed: the 2905 case where paths may begin with one of several trusted CAs; and where 2906 compatibility with the PEM architecture is required. 2908 Section 6.3 describes the steps necessary to determine if a 2909 certificate is revoked or on hold status when CRLs are the revocation 2910 mechanism used by the certificate issuer. 2912 6.1 Basic Path Validation 2914 This text describes an algorithm for X.509 path processing. A 2915 conformant implementation MUST include an X.509 path processing 2916 procedure that is functionally equivalent to the external behavior of 2917 this algorithm. However, support for some of the certificate 2918 extensions processed in this algorithm are OPTIONAL for compliant 2919 implementations. Clients that do not support these extensions MAY 2920 omit the corresponding steps in the path validation algorithm. 2922 For example, clients are NOT REQUIRED to support the policy mapping 2923 extension. Clients that do not support this extension MAY omit the 2924 path validation steps where policy mappings are processed. Note that 2925 clients MUST reject the certificate if it contains an unsupported 2926 critical extension. 2928 The algorithm presented in this section validates the certificate 2929 with respect to the current date and time. A conformant 2930 implementation MAY also support validation with respect to some point 2931 in the past. Note that mechanisms are not available for validating a 2932 certificate with respect to a time outside the certificate validity 2933 period. 2935 The trust anchor is an input to the algorithm. There is no 2936 requirement that the same trust anchor be used to validate all 2937 certification paths. Different trust anchors MAY be used to validate 2938 different paths, as discussed further in Section 6.2. 2940 The primary goal of path validation is to verify the binding between 2941 a subject distinguished name or a subject alternative name and 2942 subject public key, as represented in the end entity certificate, 2943 based on the public key of the trust anchor. This requires obtaining 2944 a sequence of certificates that support that binding. The procedure 2945 performed to obtain this sequence of certificates is outside the 2946 scope of this specification. 2948 To meet this goal, the path validation process verifies, among other 2949 things, that a prospective certification path (a sequence of n 2950 certificates) satisfies the following conditions: 2952 (a) for all x in {1, ..., n-1}, the subject of certificate x is 2953 the issuer of certificate x+1; 2955 (b) certificate 1 is issued by the trust anchor; 2957 (c) certificate n is the certificate to be validated; and 2959 (d) for all x in {1, ..., n}, the certificate was valid at the 2960 time in question. 2962 A particular certification path may not, however, be appropriate for 2963 all applications. Therefore, an application MAY augment this 2964 algorithm to further limit the set of valid paths. The path 2965 validation process also determines the set of certificate policies 2966 that are valid for this path, based on the certificate policies 2967 extension, policy mapping extension, policy constraints extension, 2968 and inhibit any-policy extension. To achieve this, the path 2969 validation algorithm constructs a valid policy tree. If the set of 2970 certificate policies that are valid for this path is not empty, then 2971 the result will be a valid policy tree of depth n, otherwise the 2972 result will be a null valid policy tree. 2974 A certificate is self-issued if the DNs that appear in the subject 2975 and issuer fields are identical and are not empty. In general, the 2976 issuer and subject of the certificates that make up a path are 2977 different for each certificate. However, a CA may issue a 2978 certificate to itself to support key rollover or changes in 2979 certificate policies. These self-issued certificates are not counted 2980 when evaluating path length or name constraints. 2982 This section presents the algorithm in four basic steps: (1) 2983 initialization, (2) basic certificate processing, (3) preparation for 2984 the next certificate, and (4) wrap-up. Steps (1) and (4) are 2985 performed exactly once. Step (2) is performed for all certificates 2986 in the path. Step (3) is performed for all certificates in the path 2987 except the final certificate. Figure 2 provides a high-level 2988 flowchart of this algorithm. 2990 +-------+ 2991 | START | 2992 +-------+ 2993 | 2994 V 2995 +----------------+ 2996 | Initialization | 2997 +----------------+ 2998 | 2999 +<--------------------+ 3000 | | 3001 V | 3002 +----------------+ | 3003 | Process Cert | | 3004 +----------------+ | 3005 | | 3006 V | 3007 +================+ | 3008 | IF Last Cert | | 3009 | in Path | | 3010 +================+ | 3011 | | | 3012 THEN | | ELSE | 3013 V V | 3014 +----------------+ +----------------+ | 3015 | Wrap up | | Prepare for | | 3016 +----------------+ | Next Cert | | 3017 | +----------------+ | 3018 V | | 3019 +-------+ +--------------+ 3020 | STOP | 3021 +-------+ 3023 Figure 2. Certification Path Processing Flowchart 3025 6.1.1 Inputs 3027 This algorithm assumes the following seven inputs are provided to the 3028 path processing logic: 3030 (a) a prospective certification path of length n. 3032 (b) the current date/time. 3034 (c) user-initial-policy-set: A set of certificate policy 3035 identifiers naming the policies that are acceptable to the 3036 certificate user. The user-initial-policy-set contains the special 3037 value any-policy if the user is not concerned about certificate 3038 policy. 3040 (d) trust anchor information, describing a CA that serves as a 3041 trust anchor for the certification path. The trust anchor 3042 information includes: 3044 (1) the trusted issuer name, 3045 (2) the trusted public key algorithm, 3047 (3) the trusted public key, and 3049 (4) optionally, the trusted public key parameters associated 3050 with the public key. 3052 The trust anchor information may be provided to the path 3053 processing procedure in the form of a self-signed certificate. 3054 The trusted anchor information is trusted because it was delivered 3055 to the path processing procedure by some trustworthy out-of-band 3056 procedure. If the trusted public key algorithm requires 3057 parameters, then the parameters are provided along with the 3058 trusted public key. 3060 (e) initial-policy-mapping-inhibit, which indicates if policy 3061 mapping is allowed in the certification path. 3063 (f) initial-explicit-policy, which indicates if the path must be 3064 valid for at least one of the certificate policies in the user- 3065 initial-policy-set. 3067 (g) initial-any-policy-inhibit, which indicates whether the any- 3068 policy OID should be processed if it is included in a certificate. 3070 6.1.2 Initialization 3072 The initialization phase establishes eleven state variables based 3073 upon the seven inputs: 3075 (a) valid_policy_tree: A tree of certificate policies with their 3076 optional qualifiers; each of the leaves of the tree represents a 3077 valid policy at this stage in the certification path validation. 3078 If valid policies exist at this stage in the certification path 3079 validation, the depth of the tree is equal to the number of 3080 certificates in the chain that have been processed. If valid 3081 policies do not exist at this stage in the certification path 3082 validation, the tree is set to NULL. Once the tree is set to NULL, 3083 policy processing ceases. 3085 Each node in the valid_policy_tree includes four data objects: the 3086 valid policy, a set of associated policy qualifiers, a set of one 3087 or more expected policy values, and a criticality indicator. If 3088 the node is at depth x, the components of the node have the 3089 following semantics: 3091 (1) The valid_policy is a single policy OID representing a 3092 valid policy for the path of length x. 3094 (2) The qualifier_set is a set of policy qualifiers associated 3095 with the valid policy in certificate x. 3097 (3) The criticality_indicator indicates whether the 3098 certificate policy extension in certificate x was marked as 3099 critical. 3101 (4) The expected_policy_set contains one or more policy OIDs 3102 that would satisfy this policy in the certificate x+1. 3104 The initial value of the valid_policy_tree is a single node with 3105 valid_policy any-policy, an empty qualifier_set, an 3106 expected_policy_set with the single value any-policy, and a 3107 criticality_indicator of FALSE. This node is considered to be at 3108 depth zero. 3110 Figure 3 is a graphic representation of the initial state of the 3111 valid_policy_tree. Additional figures will use this format to 3112 describe changes in the valid_policy_tree during path processing. 3114 +----------------+ 3115 | any-policy | <---- valid_policy 3116 +----------------+ 3117 | {} | <---- qualifier_set 3118 +----------------+ 3119 | FALSE | <---- criticality_indicator 3120 +----------------+ 3121 | {any-policy} | <---- expected_policy_set 3122 +----------------+ 3124 Figure 3. Initial value of the valid_policy_tree state variable 3126 (b) permitted_subtrees: A set of root names for each name type 3127 (e.g., X.500 distinguished names, email addresses, or ip 3128 addresses) defining a set of subtrees within which all subject 3129 names in subsequent certificates in the certification path MUST 3130 fall. This variable includes a set for each name type: the 3131 initial value for the set for Distinguished Names is the set of 3132 all Distinguished names; the initial value for the set of RFC822 3133 names is the set of all RFC822 names, etc. 3135 (c) excluded_subtrees: A set of root names for each name type 3136 (e.g., X.500 distinguished names, email addresses, or ip 3137 addresses) defining a set of subtrees within which no subject name 3138 in subsequent certificates in the certification path may fall. 3139 This variable includes a set for each name type, and the initial 3140 value for each set is empty. 3142 (d) explicit_policy: an integer which indicates if a non-NULL 3143 valid_policy_tree is required. The integer indicates the number of 3144 non-self-issued certificates to be processed before this 3145 requirement is imposed. Once set, this variable may be decreased, 3146 but may not be increased. That is, if a certificate in the path 3147 requires a non-NULL valid_policy_tree, a later certificate can not 3148 remove this requirement. If initial-explicit-policy is set, then 3149 the initial value is 0, otherwise the initial value is n+1. 3151 (e) inhibit_any-policy: an integer which indicates whether the 3152 any-policy policy identifier is considered a match. The integer 3153 indicates the number of non-self-issued certificates to be 3154 processed before the any-policy OID, if asserted in a certificate, 3155 is ignored. Once set, this variable may be decreased, but may not 3156 be increased. That is, if a certificate in the path inhibits 3157 processing of any-policy, a later certificate can not permit it. 3158 If initial-any-policy-inhibit is set, then the initial value is 0, 3159 otherwise the initial value is n+1. 3161 (f) policy_mapping: an integer which indicates if policy mapping 3162 is permitted. The integer indicates the number of non-self-issued 3163 certificates to be processed before policy mapping is inhibited. 3164 Once set, this variable may be decreased, but may not be 3165 increased. That is, if a certificate in the path specifies policy 3166 mapping is not permitted, it can not be overridden by a later 3167 certificate. If initial-policy-mapping-inhibit is set, then the 3168 initial value is 0, otherwise the initial value is n+1. 3170 (g) working_public_key_algorithm: the digital signature algorithm 3171 used to verify the signature of a certificate. The 3172 working_public_key_algorithm is initialized from the trusted 3173 public key algorithm provided in the trust anchor information. 3175 (h) working_public_key: the public key used to verify the 3176 signature of a certificate. The working_public_key is initialized 3177 from the trusted public key provided in the trust anchor 3178 information. 3180 (i) working_public_key_parameters: parameters associated with the 3181 current public key, that may be required to verify a signature 3182 (depending upon the algorithm). The working_public_key_parameters 3183 variable is initialized from the trusted public key parameters 3184 provided in the trust anchor information. 3186 (j) working_issuer_name: the issuer distinguished name expected 3187 in the next certificate in the chain. The working_issuer_name is 3188 initialized to the trusted issuer provided in the trust anchor 3189 information. 3191 (k) max_path_length: this integer is initialized to n, is 3192 decremented for each non-self-issued certificate in the path, and 3193 may be reduced to the value in the path length constraint field 3194 within the basic constraints extension of a CA certificate. 3196 Upon completion of the initialization steps, perform the basic 3197 certificate processing steps specified in 6.1.3. 3199 6.1.3 Basic Certificate Processing 3201 The basic path processing actions to be performed for certificate i 3202 are listed below. 3204 (a) Verify the basic certificate information. The certificate 3205 MUST satisfy each of the following: 3207 (1) The certificate was signed with the 3208 working_public_key_algorithm using the working_public_key and 3209 the working_public_key_parameters. 3211 (2) The certificate validity period includes the current time. 3213 (3) At the current time, the certificate is not revoked and is 3214 not on hold status. This may be determined by obtaining the 3215 appropriate CRL (section 6.3), status information, or by out- 3216 of-band mechanisms. 3218 (4) The certificate issuer name is the working_issuer_name. 3220 (b) If certificate i is self-issued and it is not the final 3221 certificate in the path, skip this step for certificate i. 3222 Otherwise, verify that the subject name is within one of the 3223 permitted_subtrees for X.500 distinguished names, and verify that 3224 each of the alternative names in the subjectAltName extension 3225 (critical or non-critical) is within one of the permitted_subtrees 3226 for that name type. 3228 (c) If certificate i is self-issued and it is not the final 3229 certificate in the path, skip this step for certificate i. 3230 Otherwise, verify that the subject name is not within one of the 3231 excluded_subtrees for X.500 distinguished names, and verify that 3232 each of the alternative names in the subjectAltName extension 3233 (critical or non-critical) is not within one of the 3234 excluded_subtrees for that name type. 3236 (d) If the certificate policies extension is present in the 3237 certificiate and the valid_policy_tree is not NULL, process the 3238 policy information by performing the following steps in order: 3240 (1) For each policy P not equal to any-policy in the 3241 certificate policies extension, let P-OID denote the OID in 3242 policy P and P-Q denote the qualifier set for policy P. 3243 Perform the following steps in order: 3245 (i) If the valid_policy_tree includes a node of depth i-1 3246 where P-OID is in the expected_policy_set, create a child 3247 node as follows: set the valid_policy to OID-P; set the 3248 qualifier_set to P-Q, and set the expected_policy_set to {P- 3249 OID}. 3251 For example, consider a valid_policy_tree with a node of 3252 depth i-1 where the expected_policy_set is {Gold, White}. 3253 Assume the certificate policies Gold and Silver appear in 3254 the certificate policies extension of certificate i. The 3255 Gold policy is matched but the Silver policy is not. This 3256 rule will generate a child node of depth i for the Gold 3257 policy. The result is shown as Figure 4. 3259 |-----------------| 3260 | Red | 3261 |-----------------| 3262 | {} | 3263 |-----------------| node of depth i-1 3264 | FALSE | 3265 |-----------------| 3266 | {Gold, White} | 3267 |-----------------| 3268 | 3269 | 3270 | 3271 V 3272 |-----------------| 3273 | Gold | 3274 |-----------------| 3275 | {} | 3276 |-----------------| node of depth i 3277 | uninitialized | 3278 |-----------------| 3279 | {Gold} | 3280 |-----------------| 3282 Figure 4. Processing an exact match 3284 (ii) If there was no match in step (i) and the 3285 valid_policy_tree includes a node of depth i-1 with the 3286 valid policy any-policy, generate a child node with the 3287 following values: set the valid_policy to P-OID; set the 3288 qualifier_set to P-Q, and set the expected_policy_set to {P- 3289 OID}. 3291 For example, consider a valid_policy_tree with a node of 3292 depth i-1 where the valid_policy is any-policy. Assume the 3293 certificate policies Gold and Silver appear in the 3294 certificate policies extension of certificate i. The Gold 3295 policy does not have a qualifier, but the Silver policy has 3296 the qualifier Q-Silver. If Gold and Silver were not matched 3297 in (i) above, this rule will generate two child nodes of 3298 depth i, one for each policy. The result is shown as Figure 3299 5. 3301 |-----------------| 3302 | any-policy | 3303 |-----------------| 3304 | {} | 3305 |-----------------| node of depth i-1 3306 | FALSE | 3307 |-----------------| 3308 | {any-policy} | 3309 |-----------------| 3310 / \ 3311 / \ 3312 / \ 3313 / \ 3314 |-----------------| |-----------------| 3315 | Gold | | Silver | 3316 |-----------------| |-----------------| 3317 | {} | | {Q-Silver} | 3318 |-----------------| nodes of |-----------------| 3319 | uninitialized | depth i | uninitialized | 3320 |-----------------| |-----------------| 3321 | {Gold} | | {Silver} | 3322 |-----------------| |-----------------| 3324 Figure 5. Processing unmatched policies when a leaf node 3325 specifies any-policy 3327 (2) If the certificate policies extension includes the policy 3328 any-policy with the qualifier set AP-Q and inhibit_any-policy 3329 is greater than 0, then: 3331 For each node in the valid_policy_tree of depth i-1, for each 3332 value in the expected_policy_set (including any-policy) that 3333 does not appear in a child node, create a child node with the 3334 following values: set the valid_policy to the value from the 3335 expected_policy_set in the parent node; set the qualifier_set 3336 to AP-Q, and set the expected_policy_set to the value in the 3337 valid_policy from this node. 3339 For example, consider a valid_policy_tree with a node of depth 3340 i-1 where the expected_policy_set = {Gold, Silver}. Assume 3341 any-policy appears in the certificate policies extension of 3342 certificate i, but Gold and Silver do not. This rule will 3343 generate two child nodes of depth i, one for each policy. The 3344 result is shown below as Figure 6. 3346 |-----------------| 3347 | Red | 3348 |-----------------| 3349 | {} | 3350 |-----------------| node of depth i-1 3351 | FALSE | 3352 |-----------------| 3353 | {Gold, Silver} | 3354 |-----------------| 3355 / \ 3356 / \ 3357 / \ 3358 / \ 3359 |-----------------| |-----------------| 3360 | Gold | | Silver | 3361 |-----------------| |-----------------| 3362 | {} | | {} | 3363 |-----------------| nodes of |-----------------| 3364 | uninitialized | depth i | uninitialized | 3365 |-----------------| |-----------------| 3366 | {Gold} | | {Silver} | 3367 |-----------------| |-----------------| 3369 Figure 6. Processing unmatched policies when the certificate 3370 policies extension specifies any-policy 3372 (3) If there is a node in the valid_policy_tree of depth i-1 3373 or less without any child nodes, delete that node. Repeat this 3374 step until there are no nodes of depth i-1 or less without 3375 children. 3377 For example, consider the valid_policy_tree shown in Figure 7 3378 below. The two nodes at depth i-1 that are marked with an 'X' 3379 have no children, and are deleted. Applying this rule to the 3380 resulting tree will cause the node at depth i-2 that is marked 3381 with an 'Y' to be deleted. The following application of the 3382 rule does not cause any nodes to be deleted, and this step is 3383 complete. 3385 +-----------+ 3386 | | node of depth i-3 3387 +-----------+ 3388 / | \ 3389 / | \ 3390 / | \ 3391 +-----------+ +-----------+ +-----------+ 3392 | | | | | Y | nodes of 3393 +-----------+ +-----------+ +-----------+ depth i-2 3394 / \ | | 3395 / \ | | 3396 / \ | | 3397 +-----------+ +-----------+ +-----------+ +-----------+ nodes of 3398 | | | X | | | | X | depth 3399 +-----------+ +-----------+ +-----------+ +-----------+ i-1 3400 | / | \ 3401 | / | \ 3402 | / | \ 3403 +-----------+ +-----------+ +-----------+ +-----------+ nodes of 3404 | | | | | | | | depth 3405 +-----------+ +-----------+ +-----------+ +-----------+ i 3407 Figure 7. Pruning the valid_policy_tree 3409 (4) If the certificate policies extension was marked as 3410 critical, set the criticality_indicator in all nodes of depth i 3411 to TRUE. If the certificate policies extension was not marked 3412 critical, set the criticality_indicator in all nodes of depth i 3413 to FALSE. 3415 (e) If the certificate policies extension is not present, set the 3416 valid_policy_tree to NULL. 3418 (f) Verify that either explicit_policy is greater than 0 or the 3419 valid_policy_tree is not equal to NULL; 3421 If any of steps (a), (b), (c), or (f) fails, the procedure 3422 terminates, returning a failure indication and an appropriate reason. 3424 If i is not equal to n, continue by performing the preparatory steps 3425 listed in 6.1.4. If i is equal to n, perform the wrap-up steps 3426 listed in 6.1.5. 3428 6.1.4 Preparation for Certificate i+1 3430 To prepare for processing of certificate i+1, perform the following 3431 steps for certificate i: 3433 (a) If a policy mapping extension is present, verify that the 3434 special value any-policy does not appear as an issuerDomainPolicy 3435 or a subjectDomainPolicy. 3437 (b) If a policy mapping extension is present, then for each 3438 issuerDomainPolicy ID-P in the policy mapping extension: 3440 (1) If the policy_mapping variable is greater than 0, for each 3441 node in the valid_policy_tree of depth i where ID-P is the 3442 valid_policy, set expected_policy_set to the set of 3443 subjectDomainPolicy values that are specified as equivalent to 3444 ID-P by the policy mapping extension. 3446 If no node of depth i in the valid_policy_tree has a 3447 valid_policy of ID-P but there is a node of depth i with a 3448 valid_policy of any-policy, then generate a child node of the 3449 node of depth i-1 that has a valid_policy of any-policy as 3450 follows: 3452 (i) set the valid_policy to ID-P; 3454 (ii) set the qualifier_set to the qualifier set of the 3455 policy any-policy in the certificate policies extension of 3456 certificate i; 3458 (iii) set the criticality_indicator to the criticality of 3459 the certificate policies extension of certificate i; 3461 (iv) and set the expected_policy_set to the set of 3462 subjectDomainPolicy values that are specified as equivalent 3463 to ID-P by the policy mappings extension. 3465 (2) If the policy_mapping variable is equal to 0: 3467 (i) delete each node of depth i in the valid_policy_tree 3468 where ID-P is the valid_policy. 3470 (ii) If there is a node in the valid_policy_tree of depth 3471 i-1 or less without any child nodes, delete that node. 3472 Repeat this step until there are no nodes of depth i-1 or 3473 less without children. 3475 (c) Assign the certificate subject name to working_issuer_name. 3477 (d) Assign the certificate subjectPublicKey to 3478 working_public_key. 3480 (e) If the subjectPublicKeyInfo field of the certificate contains 3481 an algorithm field with non-null parameters, assign the parameters 3482 to the working_public_key_parameters variable. 3484 If the subjectPublicKeyInfo field of the certificate contains an 3485 algorithm field with null parameters or parameters are omitted, 3486 compare the certificate subjectPublicKey algorithm to the 3487 working_public_key_algorithm. If the certificate subjectPublicKey 3488 algorithm and the working_public_key_algorithm are different, set 3489 the working_public_key_parameters to null. 3491 (f) Assign the certificate subjectPublicKey algorithm to the 3492 working_public_key_algorithm variable. 3494 (g) If a name constraints extension is included in the 3495 certificate, modify the permitted_subtrees and excluded_subtrees 3496 state variables as follows: 3498 (1) If permittedSubtrees is present in the certificate, set 3499 the permitted_subtrees state variable to the intersection of 3500 its previous value and the value indicated in the extension 3501 field. If permittedSubtrees does not include a particular name 3502 type, the permitted_subtrees state variable is unchanged for 3503 that name type. For example, the intersection of the name 3504 spaces nist.gov and csrc.nist.gov is csrc.nist.gov. And, the 3505 intersection of nist.gov and rsasecurity.com is the empty set. 3507 (2) If excludedSubtrees is present in the certificate, set the 3508 excluded_subtrees state variable to the union of its previous 3509 value and the value indicated in the extension field. If 3510 excludedSubtrees does not include a particular name type, the 3511 excluded_subtrees state variable is unchanged for that name 3512 type. For example, the union of the name spaces nist.gov and 3513 csrc.nist.gov is nist.gov. And, the union of nist.gov and 3514 rsasecurity.com is both name spaces. 3516 (h) If the issuer and subject names are not identical: 3518 (1) If explicit_policy is not 0, decrement explicit_policy by 3519 1. 3521 (2) If policy_mapping is not 0, decrement policy_mapping by 1. 3523 (3) If inhibit_any-policy is not 0, decrement inhibit_any- 3524 policy by 1. 3526 (i) If a policy constraints extension is included in the 3527 certificate, modify the explicit_policy and policy_mapping state 3528 variables as follows: 3530 (1) If requireExplicitPolicy is present and is less than 3531 explicit_policy, set explicit_policy to the value of 3532 requireExplicitPolicy. 3534 (2) If inhibitPolicyMapping is present and is less than 3535 policy_mapping, set policy_mapping to the value of 3536 inhibitPolicyMapping. 3538 (j) If the inhibitAnyPolicy extension is included in the 3539 certificate and is less than inhibit_any-policy, set inhibit_any- 3540 policy to the value of inhibitAnyPolicy. 3542 (k) Verify that the certificate is a CA certificate (as specified 3543 in a basicConstraints extension or as verified out-of-band). 3545 (l) If the certificate was not self-issued, verify that 3546 max_path_length is greater than zero and decrement max_path_length 3547 by 1. 3549 (m) If pathLengthConstraint is present in the certificate and is 3550 less than max_path_length, set max_path_length to the value of 3551 pathLengthConstraint. 3553 (n) If a key usage extension is present, verify that the 3554 keyCertSign bit is set. 3556 (o) Recognize and process any other critical extension present in 3557 the certificate. Process any other recognized non-critical 3558 extension present in the certificate. 3560 If check (a), (k), (l), (n) or (o) fails, the procedure terminates, 3561 returning a failure indication and an appropriate reason. 3563 If (a), (k), (l), (n) and (o) have completed successfully, increment 3564 i and perform the basic certificate processing specified in 6.1.2. 3566 6.1.5 Wrap-up procedure 3568 To complete the processing of the end entity certificate, perform the 3569 following steps for certificate n: 3571 (a) If certificate n was not self-issued and explicit_policy is 3572 not 0, decrement explicit_policy by 1. 3574 (b) If a policy constraints extension is included in the 3575 certificate and requireExplicitPolicy is present and has a value 3576 of 0, set the explicit_policy state variable to 0. 3578 (c) Assign the certificate subjectPublicKey to 3579 working_public_key. 3581 (d) If the subjectPublicKeyInfo field of the certificate contains 3582 an algorithm field with non-null parameters, assign the parameters 3583 to the working_public_key_parameters variable. 3585 If the subjectPublicKeyInfo field of the certificate contains an 3586 algorithm field with null parameters or parameters are omitted, 3587 compare the certificate subjectPublicKey algorithm to the 3588 working_public_key_algorithm. If the certificate subjectPublicKey 3589 algorithm and the working_public_key_algorithm are different, set 3590 the working_public_key_parameters to null. 3592 (e) Assign the certificate subjectPublicKey algorithm to the 3593 working_public_key_algorithm variable. 3595 (f) Recognize and process any other critical extension present in 3596 the certificate n. Process any other recognized non-critical 3597 extension present in certificate n. 3599 (g) Calculate the intersection of the valid_policy_tree and the 3600 user-initial-policy-set, as follows: 3602 (i) If the valid_policy_tree is NULL, the intersection is 3603 NULL. 3605 (ii) If the valid_policy_tree is not NULL and the user- 3606 initial-policy-set is any-policy, the intersection is the 3607 entire valid_policy_tree. 3609 (iii) If the valid_policy_tree is not NULL and the user- 3610 initial-policy-set is not any-policy, calculate the 3611 intersection of the valid_policy_tree and the user-initial- 3612 policy-set as follows: 3614 1. Determine the set of policy nodes whose ancestor nodes 3615 have a valid_policy of any-policy. This is the 3616 valid_policy_node_set. 3618 2. If the valid_policy of any node in the 3619 valid_policy_node_set is not in the user-initial-policy-set 3620 and is not any-policy, delete this node and all its 3621 children. 3623 3. If there is a node in the valid_policy_tree of depth n-1 3624 or less without any child nodes, delete that node. Repeat 3625 this step until there are no nodes of depth n-1 or less 3626 without children. 3628 If either (1) the value of explicit_policy variable is greater than 3629 zero, or (2) the valid_policy_tree is not NULL, then path processing 3630 has succeeded. 3632 6.1.6 Outputs 3634 If path processing succeeds, the procedure terminates, returning a 3635 success indication together with final value of the 3636 valid_policy_tree, the working_public_key, the 3637 working_public_key_algorithm, and the working_public_key_parameters. 3639 6.2 Using the Path Validation Algorithm 3641 The path validation algorithm describes the process of validating a 3642 single certification path. While each certification path begins with 3643 a specific trust anchor, there is no requirement that all 3644 certification paths validated by a particular system share a single 3645 trust anchor. An implementation that supports multiple trust anchors 3646 MAY augment the algorithm presented in section 6.1 to further limit 3647 the set of valid certification paths which begin with a particular 3648 trust anchor. For example, an implementation MAY modify the 3649 algorithm to apply name constraints to a specific trust anchor during 3650 the initialization phase, or the application MAY require the presence 3651 of a particular alternative name form in the end entity certificate, 3652 or the application MAY impose requirements on application-specific 3653 extensions. Thus, the path validation algorithm presented in section 3654 6.1 defines the minimum conditions for a path to be considered valid. 3656 The selection of one or more trusted CAs is a local decision. A 3657 system may provide any one of its trusted CAs as the trust anchor for 3658 a particular path. The inputs to the path validation algorithm may 3659 be different for each path. The inputs used to process a path may 3660 reflect application-specific requirements or limitations in the trust 3661 accorded a particular trust anchor. For example, a trusted CA may 3662 only be trusted for a particular certificate policy. This 3663 restriction can be expressed through the inputs to the path 3664 validation procedure. 3666 It is also possible to specify an extended version of the above 3667 certification path processing procedure which results in default 3668 behavior identical to the rules of PEM [RFC 1422]. In this extended 3669 version, additional inputs to the procedure are a list of one or more 3670 Policy Certification Authority (PCA) names and an indicator of the 3671 position in the certification path where the PCA is expected. At the 3672 nominated PCA position, the CA name is compared against this list. 3674 If a recognized PCA name is found, then a constraint of 3675 SubordinateToCA is implicitly assumed for the remainder of the 3676 certification path and processing continues. If no valid PCA name is 3677 found, and if the certification path cannot be validated on the basis 3678 of identified policies, then the certification path is considered 3679 invalid. 3681 6.3 CRL Validation 3683 This section describes the steps necessary to determine if a 3684 certificate is revoked or on hold status when CRLs are the revocation 3685 mechanism used by the certificate issuer. Conforming implementations 3686 that support CRLs are not required to implement this algorithm, but 3687 they MUST be functionally equivalent to the external behavior 3688 resulting from this procedure. Any algorithm may be used by a 3689 particular implementation so long as it derives the correct result. 3691 This algorithm assumes that all of the needed CRLs are available in a 3692 local cache. Further, if the next update time of a CRL has passed, 3693 the algorithm assumes a mechanism to fetch a current CRL and place it 3694 in the local CRL cache. 3696 This algorithm defines a set of inputs, a set of state variables, and 3697 processing steps that are performed for each certificate in the path. 3698 The algorithm output is the revocation status of the certificate. 3700 6.3.1 Revocation Inputs 3702 To support revocation processing, the algorithm requires two inputs: 3704 (a) certificate: The algorithm requires the certificate serial 3705 number and issuer name to determine whether a certificate is on a 3706 particular CRL. The basicConstraints extension is used to 3707 determine whether the supplied certificate is associated with a CA 3708 or an end entity. If present, the algorithm uses the 3709 cRLDistributionsPoint and freshestCRL extensions to determine 3710 revocation status. 3712 (b) use-deltas: This boolean input determines whether delta CRLs 3713 are applied to CRLs. 3715 Note that implementations supporting legacy PKIs, such as RFC 1422 3716 and X.509 version 1, will need an additional input indicating 3717 whether the supplied certificate is associated with a CA or an end 3718 entity. 3720 6.3.2 Initialization and Revocation State Variables 3722 To support CRL processing, the algorithm requires the following state 3723 variables: 3725 (a) reasons_mask: This variable contains the set of revocation 3726 reasons supported by the CRLs and delta CRLs processed so far. 3727 The legal members of the set are the possible revocation reason 3728 values: unspecified, keyCompromise, caCompromise, 3729 affiliationChanged, superseded, cessationOfOperation, 3730 certificateHold, privilegeWithdrawn, and aACompromise. The 3731 special value all-reasons is used to denote the set of all legal 3732 members. This variable is initialized to the empty set. 3734 (b) cert_status: This variable contains the status of the 3735 certificate. This variable may be assigned one of the following 3736 values: unspecified, keyCompromise, caCompromise, 3737 affiliationChanged, superseded, cessationOfOperation, 3738 certificateHold, removeFromCRL, privilegeWithdrawn, aACompromise, 3739 the special value UNREVOKED, or the special value UNDETERMINED. 3740 This variable is initialized to the special value UNREVOKED. 3742 (c) interim_reasons_mask: This contains the set of revocation 3743 reasons supported by the CRL or delta CRL currently being 3744 processed. 3746 Note: In some environments, it is not necessary to check all reason 3747 codes. For example, some environments are only concerned with 3748 caCompromise and keyCompromise for CA certificates. This algorithm 3749 checks all reason codes. Additional processing and state variables 3750 may be necessary to limit the checking to a subset of the reason 3751 codes. 3753 6.3.3 CRL Processing 3755 This algorithm begins by assuming the certificate is not revoked. 3756 The algorithm checks one or more CRLs until either the certificate 3757 status is determined to be revoked or sufficient CRLs have been 3758 checked to cover all reason codes. 3760 For each distribution point (DP) in the certificate CRL distribution 3761 points extension, for each corresponding CRL in the local CRL cache, 3762 while ((reasons_mask is not all-reasons) and 3763 (cert_status is UNREVOKED)) perform the following: 3765 (a) Update the local CRL cache by obtaining a complete CRL, a 3766 delta CRL, or both, as required: 3768 (1) If the current time is after the value of the CRL next 3769 update field, then do one of the following: 3771 (i) If use-deltas is set and either the certificate or the 3772 CRL contains the freshest CRL extension, obtain a delta CRL 3773 with the a next update value that is after the current time 3774 and can be used to update the locally cached CRL as 3775 specified in section 5.2.4. 3777 (ii) Update the local CRL cache with a current complete 3778 CRL, verify that the current time is before the next update 3779 value in the new CRL, and continue processing with the new 3780 CRL. If use-deltas is set, then obtain the current delta 3781 CRL that can be used to update the new locally cached 3782 complete CRL as specified in section 5.2.4. 3784 (2) If the current time is before the value of the next update 3785 field and use-deltas is set, then obtain the current delta CRL 3786 that can be used to update the locally cached complete CRL as 3787 specified in section 5.2.4. 3789 (b) Verify the issuer and scope of the complete CRL as follows: 3791 (1) If the DP includes cRLIssuer, then verify that the issuer 3792 field in the complete CRL matches cRLIssuer in the DP and that 3793 the complete CRL contains an issuing distribution point 3794 extension with the indrectCRL boolean asserted. Otherwise, 3795 verify that the CRL issuer matches the certificate issuer. 3797 (2) If the complete CRL includes an issuing distribution point 3798 (IDP) CRL extension check the following: 3800 (i) If the distribution point name is present in the IDP 3801 CRL extension and the distribution field is present in the 3802 DP, then verify that one of the names in the IDP matches one 3803 of the names in the DP. If the distribution point name is 3804 present in the IDP CRL extension and the distribution field 3805 is omitted from the DP, then verify that one of the names in 3806 the IDP matches one of the names in the cRLIssuer field of 3807 the DP. 3809 (ii) If the onlyContainsUserCerts boolean is asserted in 3810 the IDP CRL extension, verify that the certificate does not 3811 include the basic constraints extension with the cA boolean 3812 asserted. 3814 (iii) If the onlyContainsCACerts boolean is asserted in the 3815 IDP CRL extension, verify that the certificate includes the 3816 basic constraints extension with the cA boolean asserted. 3818 (iv) Verify that the onlyContainsAttributeCerts boolean is 3819 not asserted. 3821 (c) If use-deltas is set, verify the issuer and scope of the 3822 delta CRL as follows: 3824 (1) Verify that the delta CRL issuer matches complete CRL 3825 issuer. 3827 (2) If the complete CRL includes an issuing distribution point 3828 (IDP) CRL extension, verify that the delta CRL contains a 3829 matching IDP CRL extension. If the complete CRL omits an IDP 3830 CRL extension, verify that the delta CRL also omits an IDP CRL 3831 extension. 3833 (3) Verify that the delta CRL authority key identifier 3834 extension matches complete CRL authority key identifier 3835 extension. 3837 (d) Compute the interim_reasons_mask for this CRL as follows: 3839 (1) If the issuing distribution point (IDP) CRL extension is 3840 present and includes onlySomeReasons and the DP includes 3841 reasons, then set interim_reasons_mask to the intersection of 3842 reasons in the DP and onlySomeReasons in IDP CRL extension. 3844 (2) If the IDP CRL extension includes onlySomeReasons but the 3845 DP omits reasons, then set interim_reasons_mask to the value of 3846 onlySomeReasons in IDP CRL extension. 3848 (3) If the IDP CRL extension is not present or omits 3849 onlySomeReasons but the DP includes reasons, then set 3850 interim_reasons_mask to the value of DP reasons. 3852 (4) If the IDP CRL extension is not present or omits 3853 onlySomeReasons and the DP omits reasons, then set 3854 interim_reasons_mask to the special value all-reasons. 3856 (e) Verify that interim_reasons_mask includes one or more reasons 3857 that is not included in the reasons_mask. 3859 (f) Obtain and validate the certification path for the complete 3860 CRL issuer. 3862 (g) Validate the signature on the complete CRL using the public 3863 key validated in step (f). 3865 (h) If use-deltas is set, then validate the signature on the 3866 delta CRL using the public key validated in step (f). 3868 (i) If use-deltas is set, then search for the certificate on the 3869 delta CRL. If an entry is found that matches the certificate 3870 issuer and serial number as described in section 5.3.4, then set 3871 the cert_status variable to the indicated reason as follows: 3873 (1) If the reason code CRL entry extension is present, set the 3874 cert_status variable to the value of the reason code CRL entry 3875 extension. 3877 (2) If the reason code CRL entry extension is not present, set 3878 the cert_status variable to the value unspecified. 3880 (j) If (cert_status is UNREVOKED), then search for the 3881 certificate on the complete CRL. If an entry is found that 3882 matches the certificate issuer and serial number as described in 3883 section 5.3.4, then set the cert_status variable to the indicated 3884 reason as described in step (i). 3886 (k) If (cert_status is removeFromCRL), then set cert_status to 3887 UNREVOKED. 3889 If ((reasons_mask is all-reasons) OR (cert_status is not UNREVOKED)), 3890 then the revocation status has been determined, so return 3891 cert_status. 3893 If the revocation status has not been determined, repeat the process 3894 above with any available CRLs not specified in a distribution point 3895 but issued by the certificate issuer. For the processing of such a 3896 CRL, assume a DP with both the reasons and the cRLIssuer fields 3897 omitted and a distribution point name of the certificate issuer. 3898 That is, the sequence of names in fullName is generated from the 3899 certificate issuer field as well as the certificate issuerAltName 3900 extension. If the revocation status remains undetermined, then 3901 return the cert_status UNDETERMINED. 3903 7 References 3905 [ISO 10646] ISO/IEC 10646-1:1993. International Standard -- 3906 Information technology -- Universal Multiple-Octet Coded 3907 Character Set (UCS) -- Part 1: Architecture and Basic 3908 Multilingual Plane. 3910 [RFC 791] Postel, J., "Internet Protocol", RFC 791, 3911 September 1981. 3913 [RFC 822] Crocker, D., "Standard for the format of ARPA Internet 3914 text messages", RFC 822, August 1982. 3916 [RFC 1034] Mockapetris, P.V., "Domain names - concepts and 3917 facilities", RFC 1034, November 1987. 3919 [RFC 1422] Kent, S., "Privacy Enhancement for Internet Electronic 3920 Mail: Part II: Certificate-Based Key Management," 3921 RFC 1422, February 1993. 3923 [RFC 1423] Balenson, D., "Privacy Enhancement for Internet 3924 Electronic Mail: Part III: Algorithms, Modes, and 3925 Identifiers," RFC 1423, February 1993. 3927 [RFC 1510] Kohl, J., and C. Neuman, "The Kerberos Network 3928 Authentication Service (V5)," RFC 1510, September 1993. 3930 [RFC 1519] Fuller, V., T. Li, J. Yu, and K. Varadhan, "Classless 3931 Inter-Domain Routing (CIDR): An Address Assignment and 3932 Aggregation Strategy", RFC 1519, September 1993. 3934 [RFC 1738] Berners-Lee, T., L. Masinter, and M. McCahill, 3935 "Uniform Resource Locators (URL)", RFC 1738, 3936 December 1994. 3938 [RFC 1778] Howes, T., S. Kille, W. Yeong, and C. Robbins, "The 3939 String Representation of Standard Attribute Syntaxes," 3940 RFC 1778, March 1995. 3942 [RFC 1883] Deering, S., and R. Hinden. "Internet Protocol, 3943 Version 6 (IPv6) Specification", RFC 1883, December 3944 1995. 3946 [RFC 2044] F. Yergeau, F., "UTF-8, a transformation format of 3947 Unicode and ISO 10646", RFC 2044, October 1996. 3949 [RFC 2119] Bradner, S., "Key words for use in RFCs to Indicate 3950 Requirement Levels", March 1997. 3952 [RFC 2247] Kille, S., M. Wahl, A. Grimstad, R. Huber, and 3953 S. Sataluri, "Using Domains in LDAP/X.500 3954 Distinguished Names", RFC 2247, January 1998. 3956 [RFC 2252] Wahl, M., A. Coulbeck, T. Howes, and S. Kille, 3957 "Lightweight Directory Access Protocol (v3): 3958 Attribute Syntax Definitions", RFC 2252, 3959 December 1997. 3961 [RFC 2277] Alvestrand, H., "IETF Policy on Character Sets and 3962 Languages", January 1998. 3964 [RFC 2279] Yergeau, F., "UTF-8, a transformation format of 3965 ISO 10646", RFC 2279, January 1998. 3967 [RFC 2459] Housley, R., W. Ford, W. Polk, and D. Solo, "Internet 3968 X.509 Public Key Infrastructure: Certificate and CRL 3969 Profile", RFC 2459, January 1999. 3971 [RFC 2560] Myers, M., R. Ankney, A. Malpani, S. Galperin, and 3972 C. Adams, "Online Certificate Status Protocal - OCSP", 3973 June 1999. 3975 [SDN.701] SDN.701, "Message Security Protocol 4.0", Revision A, 3976 1997-02-06. 3978 [X.208] CCITT Recommendation X.208: Specification of Abstract 3979 Syntax Notation One (ASN.1), 1988. 3981 [X.501] ITU-T Recommendation X.501: Information 3982 Technology - Open Systems Interconnection - The 3983 Directory: Models, 1993. 3985 [X.509] ITU-T Recommendation X.509 (1997 E): Information 3986 Technology - Open Systems Interconnection - The 3987 Directory: Authentication Framework, June 1997. 3989 [X.520] ITU-T Recommendation X.520: Information 3990 Technology - Open Systems Interconnection - The 3991 Directory: Selected Attribute Types, 1993. 3993 [X.660] ITU-T Recommendation X.660: [*** Get Info ***] 3995 [X9.55] ANSI X9.55-1995, Public Key Cryptography For The 3996 Financial Services Industry: Extensions To Public 3997 Key Certificates And Certificate Revocation Lists, 3998 8 December, 1995. 4000 [PKINIT] Tung, B., C. Neuman, M. Hur, A. Medvinsky, 4001 S. Medvinsky, J. Wray, and J. Trostle, "Public Key 4002 Cryptography for Initial Authentciaion in Kerberos," 4003 draft-ietf-cat-kerberos-pk-init-13.txt, March 2001. 4005 [PKIXALGS] Bassham, L., R. Housley, and W. Polk, "Internet X.509 4006 Public Key Infrastructure Representation of Public Keys 4007 and Digital Signatures," 4008 draft-ietf-pkix-ipki-pkalgs-02.txt, March 2001. 4010 [PKIXTSA] Cain, P., D. Pinkas, and R. Zuccherato, "Internet 4011 X.509 Public Key Infrastructure Time Stamp Protocol," 4012 draft-ietf-pkix-time-stamp-13.txt, January 2001. 4014 8 Intellectual Property Rights 4016 The IETF has been notified of intellectual property rights claimed in 4017 regard to some or all of the specification contained in this 4018 document. For more information consult the online list of claimed 4019 rights (see http://www.ietf.org/ipr.html). 4021 The IETF takes no position regarding the validity or scope of any 4022 intellectual property or other rights that might be claimed to 4023 pertain to the implementation or use of the technology described in 4024 this document or the extent to which any license under such rights 4025 might or might not be available; neither does it represent that it 4026 has made any effort to identify any such rights. Information on the 4027 IETF's procedures with respect to rights in standards-track and 4028 standards-related documentation can be found in BCP-11. Copies of 4029 claims of rights made available for publication and any assurances of 4030 licenses to be made available, or the result of an attempt made to 4031 obtain a general license or permission for the use of such 4032 proprietary rights by implementors or users of this specification can 4033 be obtained from the IETF Secretariat. 4035 9 Security Considerations 4037 The majority of this specification is devoted to the format and 4038 content of certificates and CRLs. Since certificates and CRLs are 4039 digitally signed, no additional integrity service is necessary. 4040 Neither certificates nor CRLs need be kept secret, and unrestricted 4041 and anonymous access to certificates and CRLs has no security 4042 implications. 4044 However, security factors outside the scope of this specification 4045 will affect the assurance provided to certificate users. This 4046 section highlights critical issues to be considered by implementers, 4047 administrators, and users. 4049 The procedures performed by CAs and RAs to validate the binding of 4050 the subject's identity to their public key greatly affect the 4051 assurance that ought to be placed in the certificate. Relying 4052 parties might wish to review the CA's certificate practice statement. 4053 This is particularly important when issuing certificates to other 4054 CAs. 4056 The use of a single key pair for both signature and other purposes is 4057 strongly discouraged. Use of separate key pairs for signature and 4058 key management provides several benefits to the users. The 4059 ramifications associated with loss or disclosure of a signature key 4060 are different from loss or disclosure of a key management key. Using 4061 separate key pairs permits a balanced and flexible response. 4062 Similarly, different validity periods or key lengths for each key 4063 pair may be appropriate in some application environments. 4064 Unfortunately, some legacy applications (e.g., SSL) use a single key 4065 pair for signature and key management. 4067 The protection afforded private keys is a critical security factor. 4068 On a small scale, failure of users to protect their private keys will 4069 permit an attacker to masquerade as them, or decrypt their personal 4070 information. On a larger scale, compromise of a CA's private signing 4071 key may have a catastrophic effect. If an attacker obtains the 4072 private key unnoticed, the attacker may issue bogus certificates and 4073 CRLs. Existence of bogus certificates and CRLs will undermine 4074 confidence in the system. If such a compromise is detected, all 4075 certificates issued to the compromised CA MUST be revoked, preventing 4076 services between its users and users of other CAs. Rebuilding after 4077 such a compromise will be problematic, so CAs are advised to 4078 implement a combination of strong technical measures (e.g., tamper- 4079 resistant cryptographic modules) and appropriate management 4080 procedures (e.g., separation of duties) to avoid such an incident. 4082 Loss of a CA's private signing key may also be problematic. The CA 4083 would not be able to produce CRLs or perform normal key rollover. 4084 CAs SHOULD maintain secure backup for signing keys. The security of 4085 the key backup procedures is a critical factor in avoiding key 4086 compromise. 4088 The availability and freshness of revocation information affects the 4089 degree of assurance that ought to be placed in a certificate. While 4090 certificates expire naturally, events may occur during its natural 4091 lifetime which negate the binding between the subject and public key. 4092 If revocation information is untimely or unavailable, the assurance 4093 associated with the binding is clearly reduced. Relying parties 4094 might not be able to process every critical extension that can appear 4095 in a CRL. CAs SHOULD take extra care when making revocation 4096 information available only through CRLs that contain critical 4097 extensions, particularly if support for those extensions is not 4098 mandated by this profile. For example, if revocation information is 4099 supplied using a combination of delta CRLs and full CRLs, and the 4100 delta CRLs are issued more frequently than the full CRLs, then 4101 relying parties that cannot handle the critical extensions related to 4102 delta CRL processing will not be able to obtain the most recent 4103 revocation information. Alternatively, if a full CRL is issued 4104 whenever a delta CRL is issued, then timely revocation information 4105 will be available to all relying parties. Similarly, implementations 4106 of the certification path validation mechanism described in section 6 4107 that omit revocation checking provide less assurance than those that 4108 support it. 4110 The path validation algorithm depends on the certain knowledge of the 4111 public keys (and other information) about one or more trusted CAs. 4112 The decision to trust a CA is an important decision as it ultimately 4113 determines the trust afforded a certificate. The authenticated 4114 distribution of trusted CA public keys (usually in the form of a 4115 "self-signed" certificate) is a security critical out-of-band process 4116 that is beyond the scope of this specification. 4118 In addition, where a key compromise or CA failure occurs for a 4119 trusted CA, the user will need to modify the information provided to 4120 the path validation routine. Selection of too many trusted CAs makes 4121 the trusted CA information difficult to maintain. On the other hand, 4122 selection of only one trusted CA could limit users to a closed 4123 community of users. 4125 The quality of implementations that process certificates also affects 4126 the degree of assurance provided. The path validation algorithm 4127 described in section 6 relies upon the integrity of the trusted CA 4128 information, and especially the integrity of the public keys 4129 associated with the trusted CAs. By substituting public keys for 4130 which an attacker has the private key, an attacker could trick the 4131 user into accepting false certificates. 4133 The binding between a key and certificate subject cannot be stronger 4134 than the cryptographic module implementation and algorithms used to 4135 generate the signature. Short key lengths or weak hash algorithms 4136 will limit the utility of a certificate. CAs are encouraged to note 4137 advances in cryptology so they can employ strong cryptographic 4138 techniques. In addition, CAs SHOULD decline to issue certificates to 4139 CAs or end entities that generate weak signatures. 4141 Inconsistent application of name comparison rules can result in 4142 acceptance of invalid X.509 certification paths, or rejection of 4143 valid ones. The X.500 series of specifications defines rules for 4144 comparing distinguished names that require comparison of strings 4145 without regard to case, character set, multi-character white space 4146 substring, or leading and trailing white space. This specification 4147 relaxes these requirements, requiring support for binary comparison 4148 at a minimum. 4150 CAs MUST encode the distinguished name in the subject field of a CA 4151 certificate identically to the distinguished name in the issuer field 4152 in certificates issued by that CA. If CAs use different encodings, 4153 implementations might fail to recognize name chains for paths that 4154 include this certificate. As a consequence, valid paths could be 4155 rejected. 4157 In addition, name constraints for distinguished names MUST be stated 4158 identically to the encoding used in the subject field or 4159 subjectAltName extension. If not, then name constraints stated as 4160 excludedSubTrees will not match and invalid paths will be accepted 4161 and name constraints expressed as permittedSubtrees will not match 4162 and valid paths will be rejected. To avoid acceptance of invalid 4163 paths, CAs SHOULD state name constraints for distinguished names as 4164 permittedSubtrees wherever possible. 4166 Appendix A. Psuedo-ASN.1 Structures and OIDs 4168 This section describes data objects used by conforming PKI components 4169 in an "ASN.1-like" syntax. This syntax is a hybrid of the 1988 and 4170 1993 ASN.1 syntaxes. The 1988 ASN.1 syntax is augmented with 1993 4171 UNIVERSAL Types UniversalString, BMPString and UTF8String. 4173 The ASN.1 syntax does not permit the inclusion of type statements in 4174 the ASN.1 module, and the 1993 ASN.1 standard does not permit use of 4175 the new UNIVERSAL types in modules using the 1988 syntax. As a 4176 result, this module does not conform to either version of the ASN.1 4177 standard. 4179 This appendix may be converted into 1988 ASN.1 by replacing the 4180 defintions for the UNIVERSAL Types with the 1988 catch-all "ANY". 4182 A.1 Explicitly Tagged Module, 1988 Syntax 4184 PKIX1Explicit88 { iso(1) identified-organization(3) dod(6) internet(1) 4185 security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-explicit(18) } 4187 DEFINITIONS EXPLICIT TAGS ::= 4189 BEGIN 4191 -- EXPORTS ALL -- 4193 -- IMPORTS NONE -- 4195 -- UNIVERSAL Types defined in 1993 and 1998 ASN.1 4196 -- and required by this specification 4198 UniversalString ::= [UNIVERSAL 28] IMPLICIT OCTET STRING 4199 -- UniversalString is defined in ASN.1:1993 4201 BMPString ::= [UNIVERSAL 30] IMPLICIT OCTET STRING 4202 -- BMPString is the subtype of UniversalString and models 4203 -- the Basic Multilingual Plane of ISO/IEC/ITU 10646-1 4205 UTF8String ::= [UNIVERSAL 12] IMPLICIT OCTET STRING 4206 -- The content of this type conforms to RFC 2279. 4208 -- PKIX specific OIDs 4210 id-pkix OBJECT IDENTIFIER ::= 4211 { iso(1) identified-organization(3) dod(6) internet(1) 4212 security(5) mechanisms(5) pkix(7) } 4214 -- PKIX arcs 4216 id-pe OBJECT IDENTIFIER ::= { id-pkix 1 } 4217 -- arc for private certificate extensions 4218 id-qt OBJECT IDENTIFIER ::= { id-pkix 2 } 4219 -- arc for policy qualifier types 4220 id-kp OBJECT IDENTIFIER ::= { id-pkix 3 } 4221 -- arc for extended key purpose OIDS 4222 id-ad OBJECT IDENTIFIER ::= { id-pkix 48 } 4223 -- arc for access descriptors 4225 -- policyQualifierIds for Internet policy qualifiers 4227 id-qt-cps OBJECT IDENTIFIER ::= { id-qt 1 } 4228 -- OID for CPS qualifier 4229 id-qt-unotice OBJECT IDENTIFIER ::= { id-qt 2 } 4230 -- OID for user notice qualifier 4232 -- access descriptor definitions 4234 id-ad-ocsp OBJECT IDENTIFIER ::= { id-ad 1 } 4235 id-ad-caIssuers OBJECT IDENTIFIER ::= { id-ad 2 } 4236 id-ad-timeStamping OBJECT IDENTIFIER ::= { id-ad 3 } 4237 id-ad-caRepository OBJECT IDENTIFIER ::= { id-ad 5 } 4239 -- attribute data types 4241 Attribute ::= SEQUENCE { 4242 type AttributeType, 4243 values SET OF AttributeValue } 4244 -- at least one value is required 4246 AttributeType ::= OBJECT IDENTIFIER 4248 AttributeValue ::= ANY 4250 AttributeTypeAndValue ::= SEQUENCE { 4251 type AttributeType, 4252 value AttributeValue } 4254 -- suggested naming attributes: Definition of the following 4255 -- information object set may be augmented to meet local 4256 -- requirements. Note that deleting members of the set may 4257 -- prevent interoperability with conforming implementations. 4258 -- presented in pairs: the AttributeType followed by the 4259 -- type definition for the corresponding AttributeValue 4261 --Arc for standard naming attributes 4262 id-at OBJECT IDENTIFIER ::= { joint-iso-ccitt(2) ds(5) 4 } 4264 -- Naming attributes of type X520name 4266 id-at-name AttributeType ::= { id-at 41 } 4267 id-at-surname AttributeType ::= { id-at 4 } 4268 id-at-givenName AttributeType ::= { id-at 42 } 4269 id-at-initials AttributeType ::= { id-at 43 } 4270 id-at-generationQualifier AttributeType ::= { id-at 44 } 4272 X520name ::= CHOICE { 4273 teletexString TeletexString (SIZE (1..ub-name)), 4274 printableString PrintableString (SIZE (1..ub-name)), 4275 universalString UniversalString (SIZE (1..ub-name)), 4276 utf8String UTF8String (SIZE (1..ub-name)), 4277 bmpString BMPString (SIZE (1..ub-name)) } 4279 -- Naming attributes of type X520CommonName 4281 id-at-commonName AttributeType ::= { id-at 3 } 4283 X520CommonName ::= CHOICE { 4284 teletexString TeletexString (SIZE (1..ub-common-name)), 4285 printableString PrintableString (SIZE (1..ub-common-name)), 4286 universalString UniversalString (SIZE (1..ub-common-name)), 4287 utf8String UTF8String (SIZE (1..ub-common-name)), 4288 bmpString BMPString (SIZE (1..ub-common-name)) } 4290 -- Naming attributes of type X520LocalityName 4292 id-at-localityName AttributeType ::= { id-at 7 } 4294 X520LocalityName ::= CHOICE { 4295 teletexString TeletexString (SIZE (1..ub-locality-name)), 4296 printableString PrintableString (SIZE (1..ub-locality-name)), 4297 universalString UniversalString (SIZE (1..ub-locality-name)), 4298 utf8String UTF8String (SIZE (1..ub-locality-name)), 4299 bmpString BMPString (SIZE (1..ub-locality-name)) } 4301 -- Naming attributes of type X520StateOrProvinceName 4303 id-at-stateOrProvinceName AttributeType ::= { id-at 8 } 4305 X520StateOrProvinceName ::= CHOICE { 4306 teletexString TeletexString (SIZE (1..ub-state-name)), 4307 printableString PrintableString (SIZE (1..ub-state-name)), 4308 universalString UniversalString (SIZE (1..ub-state-name)), 4309 utf8String UTF8String (SIZE (1..ub-state-name)), 4310 bmpString BMPString (SIZE(1..ub-state-name)) } 4312 -- Naming attributes of type X520OrganizationName 4314 id-at-organizationName AttributeType ::= { id-at 10 } 4316 X520OrganizationName ::= CHOICE { 4317 teletexString TeletexString 4318 (SIZE (1..ub-organization-name)), 4319 printableString PrintableString 4320 (SIZE (1..ub-organization-name)), 4321 universalString UniversalString 4322 (SIZE (1..ub-organization-name)), 4323 utf8String UTF8String 4324 (SIZE (1..ub-organization-name)), 4325 bmpString BMPString 4326 (SIZE (1..ub-organization-name)) } 4328 -- Naming attributes of type X520OrganizationalUnitName 4330 id-at-organizationalUnitName AttributeType ::= { id-at 11 } 4332 X520OrganizationalUnitName ::= CHOICE { 4333 teletexString TeletexString 4334 (SIZE (1..ub-organizational-unit-name)), 4335 printableString PrintableString 4336 (SIZE (1..ub-organizational-unit-name)), 4337 universalString UniversalString 4338 (SIZE (1..ub-organizational-unit-name)), 4339 utf8String UTF8String 4340 (SIZE (1..ub-organizational-unit-name)), 4341 bmpString BMPString 4342 (SIZE (1..ub-organizational-unit-name)) } 4344 -- Naming attributes of type X520Title 4346 id-at-title AttributeType ::= { id-at 12 } 4348 X520Title ::= CHOICE { 4349 teletexString TeletexString (SIZE (1..ub-title)), 4350 printableString PrintableString (SIZE (1..ub-title)), 4351 universalString UniversalString (SIZE (1..ub-title)), 4352 utf8String UTF8String (SIZE (1..ub-title)), 4353 bmpString BMPString (SIZE (1..ub-title)) } 4355 -- Naming attributes of type X520dnQualifier 4356 id-at-dnQualifier AttributeType ::= { id-at 46 } 4358 X520dnQualifier ::= PrintableString 4360 -- Naming attributes of type X520countryName (digraph from IS 3166) 4362 id-at-countryName AttributeType ::= { id-at 6 } 4364 X520countryName ::= PrintableString (SIZE (2)) 4366 -- Naming attributes of type X520SerialNumber 4368 id-at-serialNumber AttributeType ::= { id-at 5 } 4370 X520SerialNumber ::= PrintableString (SIZE (1..ub-serial-number)) 4372 -- Naming attributes of type DomainComponent (from RFC 2247) 4374 id-domainComponent AttributeType ::= 4375 { 0 9 2342 19200300 100 1 25 } 4377 DomainComponent ::= IA5String 4379 -- Legacy attributes 4381 pkcs-9 OBJECT IDENTIFIER ::= 4382 { iso(1) member-body(2) us(840) rsadsi(113549) pkcs(1) 9 } 4384 id-emailAddress AttributeType ::= { pkcs-9 1 } 4386 EmailAddress ::= IA5String (SIZE (1..ub-emailaddress-length)) 4388 -- naming data types -- 4390 Name ::= CHOICE { -- only one possibility for now -- 4391 rdnSequence RDNSequence } 4393 RDNSequence ::= SEQUENCE OF RelativeDistinguishedName 4395 DistinguishedName ::= RDNSequence 4397 RelativeDistinguishedName ::= 4398 SET SIZE (1 .. MAX) OF AttributeTypeAndValue 4400 -- Directory string type -- 4402 DirectoryString ::= CHOICE { 4403 teletexString TeletexString (SIZE (1..MAX)), 4404 printableString PrintableString (SIZE (1..MAX)), 4405 universalString UniversalString (SIZE (1..MAX)), 4406 utf8String UTF8String (SIZE (1..MAX)), 4407 bmpString BMPString (SIZE (1..MAX)) } 4409 -- certificate and CRL specific structures begin here 4411 Certificate ::= SEQUENCE { 4412 tbsCertificate TBSCertificate, 4413 signatureAlgorithm AlgorithmIdentifier, 4414 signature BIT STRING } 4416 TBSCertificate ::= SEQUENCE { 4417 version [0] Version DEFAULT v1, 4418 serialNumber CertificateSerialNumber, 4419 signature AlgorithmIdentifier, 4420 issuer Name, 4421 validity Validity, 4422 subject Name, 4423 subjectPublicKeyInfo SubjectPublicKeyInfo, 4424 issuerUniqueID [1] IMPLICIT UniqueIdentifier OPTIONAL, 4425 -- If present, version MUST be v2 or v3 4426 subjectUniqueID [2] IMPLICIT UniqueIdentifier OPTIONAL, 4427 -- If present, version MUST be v2 or v3 4428 extensions [3] Extensions OPTIONAL 4429 -- If present, version MUST be v3 -- } 4431 Version ::= INTEGER { v1(0), v2(1), v3(2) } 4433 CertificateSerialNumber ::= INTEGER 4435 Validity ::= SEQUENCE { 4436 notBefore Time, 4437 notAfter Time } 4439 Time ::= CHOICE { 4440 utcTime UTCTime, 4441 generalTime GeneralizedTime } 4443 UniqueIdentifier ::= BIT STRING 4445 SubjectPublicKeyInfo ::= SEQUENCE { 4446 algorithm AlgorithmIdentifier, 4447 subjectPublicKey BIT STRING } 4449 Extensions ::= SEQUENCE SIZE (1..MAX) OF Extension 4451 Extension ::= SEQUENCE { 4452 extnID OBJECT IDENTIFIER, 4453 critical BOOLEAN DEFAULT FALSE, 4454 extnValue OCTET STRING } 4456 -- CRL structures 4458 CertificateList ::= SEQUENCE { 4459 tbsCertList TBSCertList, 4460 signatureAlgorithm AlgorithmIdentifier, 4461 signature BIT STRING } 4463 TBSCertList ::= SEQUENCE { 4464 version Version OPTIONAL, 4465 -- if present, MUST be v2 4466 signature AlgorithmIdentifier, 4467 issuer Name, 4468 thisUpdate Time, 4469 nextUpdate Time OPTIONAL, 4470 revokedCertificates SEQUENCE OF SEQUENCE { 4471 userCertificate CertificateSerialNumber, 4472 revocationDate Time, 4473 crlEntryExtensions Extensions OPTIONAL 4474 -- if present, MUST be v2 4475 } OPTIONAL, 4476 crlExtensions [0] Extensions OPTIONAL 4477 -- if present, MUST be v2 -- } 4479 -- Version, Time, CertificateSerialNumber, and Extensions were 4480 -- defined earlier for use in the certificate structure 4482 AlgorithmIdentifier ::= SEQUENCE { 4483 algorithm OBJECT IDENTIFIER, 4484 parameters ANY DEFINED BY algorithm OPTIONAL } 4485 -- contains a value of the type 4486 -- registered for use with the 4487 -- algorithm object identifier value 4489 -- X.400 address syntax starts here 4491 ORAddress ::= SEQUENCE { 4492 built-in-standard-attributes BuiltInStandardAttributes, 4493 built-in-domain-defined-attributes 4494 BuiltInDomainDefinedAttributes OPTIONAL, 4495 -- see also teletex-domain-defined-attributes 4496 extension-attributes ExtensionAttributes OPTIONAL } 4497 -- [[[*** What is this comment about? OR-Name is not defined ***]]] 4498 -- The OR-address is semantically absent from the OR-name if the 4499 -- built-in-standard-attribute sequence is empty and the 4500 -- built-in-domain-defined-attributes and extension-attributes are 4501 -- both omitted. 4503 -- Built-in Standard Attributes 4505 BuiltInStandardAttributes ::= SEQUENCE { 4506 country-name CountryName OPTIONAL, 4507 administration-domain-name AdministrationDomainName OPTIONAL, 4508 network-address [0] NetworkAddress OPTIONAL, 4509 -- see also extended-network-address 4510 terminal-identifier [1] TerminalIdentifier OPTIONAL, 4511 private-domain-name [2] PrivateDomainName OPTIONAL, 4512 organization-name [3] OrganizationName OPTIONAL, 4513 -- see also teletex-organization-name 4514 numeric-user-identifier [4] NumericUserIdentifier OPTIONAL, 4515 personal-name [5] PersonalName OPTIONAL, 4516 -- see also teletex-personal-name 4517 organizational-unit-names [6] OrganizationalUnitNames OPTIONAL 4518 -- see also teletex-organizational-unit-names -- } 4520 CountryName ::= [APPLICATION 1] CHOICE { 4521 x121-dcc-code NumericString 4522 (SIZE (ub-country-name-numeric-length)), 4523 iso-3166-alpha2-code PrintableString 4524 (SIZE (ub-country-name-alpha-length)) } 4526 AdministrationDomainName ::= [APPLICATION 2] CHOICE { 4527 numeric NumericString (SIZE (0..ub-domain-name-length)), 4528 printable PrintableString (SIZE (0..ub-domain-name-length)) } 4530 NetworkAddress ::= X121Address -- see also extended-network-address 4532 X121Address ::= NumericString (SIZE (1..ub-x121-address-length)) 4534 TerminalIdentifier ::= PrintableString (SIZE (1..ub-terminal-id-length)) 4536 PrivateDomainName ::= CHOICE { 4537 numeric NumericString (SIZE (1..ub-domain-name-length)), 4538 printable PrintableString (SIZE (1..ub-domain-name-length)) } 4540 OrganizationName ::= PrintableString 4541 (SIZE (1..ub-organization-name-length)) 4542 -- see also teletex-organization-name 4544 NumericUserIdentifier ::= NumericString 4545 (SIZE (1..ub-numeric-user-id-length)) 4547 PersonalName ::= SET { 4548 surname [0] PrintableString (SIZE (1..ub-surname-length)), 4549 given-name [1] PrintableString 4550 (SIZE (1..ub-given-name-length)) OPTIONAL, 4551 initials [2] PrintableString (SIZE (1..ub-initials-length)) OPTIONAL, 4552 generation-qualifier [3] PrintableString 4553 (SIZE (1..ub-generation-qualifier-length)) OPTIONAL } 4554 -- see also teletex-personal-name 4556 OrganizationalUnitNames ::= SEQUENCE SIZE (1..ub-organizational-units) 4557 OF OrganizationalUnitName 4558 -- see also teletex-organizational-unit-names 4560 OrganizationalUnitName ::= PrintableString (SIZE 4561 (1..ub-organizational-unit-name-length)) 4563 -- Built-in Domain-defined Attributes 4565 BuiltInDomainDefinedAttributes ::= SEQUENCE SIZE 4566 (1..ub-domain-defined-attributes) OF 4567 BuiltInDomainDefinedAttribute 4569 BuiltInDomainDefinedAttribute ::= SEQUENCE { 4570 type PrintableString (SIZE 4571 (1..ub-domain-defined-attribute-type-length)), 4572 value PrintableString (SIZE 4573 (1..ub-domain-defined-attribute-value-length)) } 4575 -- Extension Attributes 4577 ExtensionAttributes ::= SET SIZE (1..ub-extension-attributes) OF 4578 ExtensionAttribute 4580 ExtensionAttribute ::= SEQUENCE { 4581 extension-attribute-type [0] INTEGER (0..ub-extension-attributes), 4582 extension-attribute-value [1] 4583 ANY DEFINED BY extension-attribute-type } 4585 -- Extension types and attribute values 4587 common-name INTEGER ::= 1 4589 CommonName ::= PrintableString (SIZE (1..ub-common-name-length)) 4591 teletex-common-name INTEGER ::= 2 4593 TeletexCommonName ::= TeletexString (SIZE (1..ub-common-name-length)) 4595 teletex-organization-name INTEGER ::= 3 4596 TeletexOrganizationName ::= 4597 TeletexString (SIZE (1..ub-organization-name-length)) 4599 teletex-personal-name INTEGER ::= 4 4601 TeletexPersonalName ::= SET { 4602 surname [0] TeletexString (SIZE (1..ub-surname-length)), 4603 given-name [1] TeletexString 4604 (SIZE (1..ub-given-name-length)) OPTIONAL, 4605 initials [2] TeletexString (SIZE (1..ub-initials-length)) OPTIONAL, 4606 generation-qualifier [3] TeletexString (SIZE 4607 (1..ub-generation-qualifier-length)) OPTIONAL } 4609 teletex-organizational-unit-names INTEGER ::= 5 4611 TeletexOrganizationalUnitNames ::= SEQUENCE SIZE 4612 (1..ub-organizational-units) OF TeletexOrganizationalUnitName 4614 TeletexOrganizationalUnitName ::= TeletexString 4615 (SIZE (1..ub-organizational-unit-name-length)) 4617 pds-name INTEGER ::= 7 4619 PDSName ::= PrintableString (SIZE (1..ub-pds-name-length)) 4621 physical-delivery-country-name INTEGER ::= 8 4623 PhysicalDeliveryCountryName ::= CHOICE { 4624 x121-dcc-code NumericString (SIZE (ub-country-name-numeric-length)), 4625 iso-3166-alpha2-code PrintableString 4626 (SIZE (ub-country-name-alpha-length)) } 4628 postal-code INTEGER ::= 9 4630 PostalCode ::= CHOICE { 4631 numeric-code NumericString (SIZE (1..ub-postal-code-length)), 4632 printable-code PrintableString (SIZE (1..ub-postal-code-length)) } 4634 physical-delivery-office-name INTEGER ::= 10 4636 PhysicalDeliveryOfficeName ::= PDSParameter 4638 physical-delivery-office-number INTEGER ::= 11 4640 PhysicalDeliveryOfficeNumber ::= PDSParameter 4642 extension-OR-address-components INTEGER ::= 12 4643 ExtensionORAddressComponents ::= PDSParameter 4645 physical-delivery-personal-name INTEGER ::= 13 4647 PhysicalDeliveryPersonalName ::= PDSParameter 4649 physical-delivery-organization-name INTEGER ::= 14 4651 PhysicalDeliveryOrganizationName ::= PDSParameter 4653 extension-physical-delivery-address-components INTEGER ::= 15 4655 ExtensionPhysicalDeliveryAddressComponents ::= PDSParameter 4657 unformatted-postal-address INTEGER ::= 16 4659 UnformattedPostalAddress ::= SET { 4660 printable-address SEQUENCE SIZE (1..ub-pds-physical-address-lines) OF 4661 PrintableString (SIZE (1..ub-pds-parameter-length)) OPTIONAL, 4662 teletex-string TeletexString 4663 (SIZE (1..ub-unformatted-address-length)) OPTIONAL } 4665 street-address INTEGER ::= 17 4667 StreetAddress ::= PDSParameter 4669 post-office-box-address INTEGER ::= 18 4671 PostOfficeBoxAddress ::= PDSParameter 4673 poste-restante-address INTEGER ::= 19 4675 PosteRestanteAddress ::= PDSParameter 4677 unique-postal-name INTEGER ::= 20 4679 UniquePostalName ::= PDSParameter 4681 local-postal-attributes INTEGER ::= 21 4683 LocalPostalAttributes ::= PDSParameter 4685 PDSParameter ::= SET { 4686 printable-string PrintableString 4687 (SIZE(1..ub-pds-parameter-length)) OPTIONAL, 4688 teletex-string TeletexString 4689 (SIZE(1..ub-pds-parameter-length)) OPTIONAL } 4691 extended-network-address INTEGER ::= 22 4693 ExtendedNetworkAddress ::= CHOICE { 4694 e163-4-address SEQUENCE { 4695 number [0] NumericString (SIZE (1..ub-e163-4-number-length)), 4696 sub-address [1] NumericString 4697 (SIZE (1..ub-e163-4-sub-address-length)) OPTIONAL }, 4698 psap-address [0] PresentationAddress } 4700 PresentationAddress ::= SEQUENCE { 4701 pSelector [0] EXPLICIT OCTET STRING OPTIONAL, 4702 sSelector [1] EXPLICIT OCTET STRING OPTIONAL, 4703 tSelector [2] EXPLICIT OCTET STRING OPTIONAL, 4704 nAddresses [3] EXPLICIT SET SIZE (1..MAX) OF OCTET STRING } 4706 terminal-type INTEGER ::= 23 4708 TerminalType ::= INTEGER { 4709 telex (3), 4710 teletex (4), 4711 g3-facsimile (5), 4712 g4-facsimile (6), 4713 ia5-terminal (7), 4714 videotex (8) } (0..ub-integer-options) 4716 -- Extension Domain-defined Attributes 4718 teletex-domain-defined-attributes INTEGER ::= 6 4720 TeletexDomainDefinedAttributes ::= SEQUENCE SIZE 4721 (1..ub-domain-defined-attributes) OF TeletexDomainDefinedAttribute 4723 TeletexDomainDefinedAttribute ::= SEQUENCE { 4724 type TeletexString 4725 (SIZE (1..ub-domain-defined-attribute-type-length)), 4726 value TeletexString 4727 (SIZE (1..ub-domain-defined-attribute-value-length)) } 4729 -- specifications of Upper Bounds MUST be regarded as mandatory 4730 -- from Annex B of ITU-T X.411 Reference Definition of MTS Parameter 4731 -- Upper Bounds 4733 -- Upper Bounds 4734 ub-name INTEGER ::= 32768 4735 ub-common-name INTEGER ::= 64 4736 ub-locality-name INTEGER ::= 128 4737 ub-state-name INTEGER ::= 128 4738 ub-organization-name INTEGER ::= 64 4739 ub-organizational-unit-name INTEGER ::= 64 4740 ub-title INTEGER ::= 64 4741 ub-serial-number INTEGER ::= 64 4742 ub-match INTEGER ::= 128 4743 ub-emailaddress-length INTEGER ::= 128 4744 ub-common-name-length INTEGER ::= 64 4745 ub-country-name-alpha-length INTEGER ::= 2 4746 ub-country-name-numeric-length INTEGER ::= 3 4747 ub-domain-defined-attributes INTEGER ::= 4 4748 ub-domain-defined-attribute-type-length INTEGER ::= 8 4749 ub-domain-defined-attribute-value-length INTEGER ::= 128 4750 ub-domain-name-length INTEGER ::= 16 4751 ub-extension-attributes INTEGER ::= 256 4752 ub-e163-4-number-length INTEGER ::= 15 4753 ub-e163-4-sub-address-length INTEGER ::= 40 4754 ub-generation-qualifier-length INTEGER ::= 3 4755 ub-given-name-length INTEGER ::= 16 4756 ub-initials-length INTEGER ::= 5 4757 ub-integer-options INTEGER ::= 256 4758 ub-numeric-user-id-length INTEGER ::= 32 4759 ub-organization-name-length INTEGER ::= 64 4760 ub-organizational-unit-name-length INTEGER ::= 32 4761 ub-organizational-units INTEGER ::= 4 4762 ub-pds-name-length INTEGER ::= 16 4763 ub-pds-parameter-length INTEGER ::= 30 4764 ub-pds-physical-address-lines INTEGER ::= 6 4765 ub-postal-code-length INTEGER ::= 16 4766 ub-surname-length INTEGER ::= 40 4767 ub-terminal-id-length INTEGER ::= 24 4768 ub-unformatted-address-length INTEGER ::= 180 4769 ub-x121-address-length INTEGER ::= 16 4771 -- Note - upper bounds on string types, such as TeletexString, are 4772 -- measured in characters. Excepting PrintableString or IA5String, a 4773 -- significantly greater number of octets will be required to hold 4774 -- such a value. As a minimum, 16 octets, or twice the specified upper 4775 -- bound, whichever is the larger, should be allowed for TeletexString. 4776 -- For UTF8String or UniversalString at least four times the upper 4777 -- bound should be allowed. 4779 END 4780 A.2 Implicitly Tagged Module, 1988 Syntax 4782 PKIX1Implicit88 { iso(1) identified-organization(3) dod(6) internet(1) 4783 security(5) mechanisms(5) pkix(7) id-mod(0) id-pkix1-implicit(19) } 4785 DEFINITIONS IMPLICIT TAGS ::= 4787 BEGIN 4789 -- EXPORTS ALL -- 4791 IMPORTS 4792 id-pe, id-kp, id-qt-unotice, id-qt-cps, 4793 -- delete following line if "new" types are supported -- 4794 BMPString, UTF8String, -- end "new" types -- 4795 ORAddress, Name, RelativeDistinguishedName, 4796 CertificateSerialNumber, Attribute, DirectoryString 4797 FROM PKIX1Explicit88 { iso(1) identified-organization(3) 4798 dod(6) internet(1) security(5) mechanisms(5) pkix(7) 4799 id-mod(0) id-pkix1-explicit(18) }; 4801 -- ISO arc for standard certificate and CRL extensions 4803 id-ce OBJECT IDENTIFIER ::= {joint-iso-ccitt(2) ds(5) 29} 4805 -- authority key identifier OID and syntax 4807 id-ce-authorityKeyIdentifier OBJECT IDENTIFIER ::= { id-ce 35 } 4809 AuthorityKeyIdentifier ::= SEQUENCE { 4810 keyIdentifier [0] KeyIdentifier OPTIONAL, 4811 authorityCertIssuer [1] GeneralNames OPTIONAL, 4812 authorityCertSerialNumber [2] CertificateSerialNumber OPTIONAL } 4813 -- authorityCertIssuer and authorityCertSerialNumber MUST both 4814 -- be present or both be absent 4816 KeyIdentifier ::= OCTET STRING 4818 -- subject key identifier OID and syntax 4820 id-ce-subjectKeyIdentifier OBJECT IDENTIFIER ::= { id-ce 14 } 4822 SubjectKeyIdentifier ::= KeyIdentifier 4824 -- key usage extension OID and syntax 4826 id-ce-keyUsage OBJECT IDENTIFIER ::= { id-ce 15 } 4827 KeyUsage ::= BIT STRING { 4828 digitalSignature (0), 4829 nonRepudiation (1), 4830 keyEncipherment (2), 4831 dataEncipherment (3), 4832 keyAgreement (4), 4833 keyCertSign (5), 4834 cRLSign (6), 4835 encipherOnly (7), 4836 decipherOnly (8) } 4838 -- private key usage period extension OID and syntax 4840 id-ce-privateKeyUsagePeriod OBJECT IDENTIFIER ::= { id-ce 16 } 4842 PrivateKeyUsagePeriod ::= SEQUENCE { 4843 notBefore [0] GeneralizedTime OPTIONAL, 4844 notAfter [1] GeneralizedTime OPTIONAL } 4845 -- either notBefore or notAfter MUST be present 4847 -- certificate policies extension OID and syntax 4849 id-ce-certificatePolicies OBJECT IDENTIFIER ::= { id-ce 32 } 4851 anyPolicy OBJECT IDENTIFIER ::= { id-ce-certificatePolicies 0 } 4853 CertificatePolicies ::= SEQUENCE SIZE (1..MAX) OF PolicyInformation 4855 PolicyInformation ::= SEQUENCE { 4856 policyIdentifier CertPolicyId, 4857 policyQualifiers SEQUENCE SIZE (1..MAX) OF 4858 PolicyQualifierInfo OPTIONAL } 4860 CertPolicyId ::= OBJECT IDENTIFIER 4862 PolicyQualifierInfo ::= SEQUENCE { 4863 policyQualifierId PolicyQualifierId, 4864 qualifier ANY DEFINED BY policyQualifierId } 4866 -- Implementations that recognize additional policy qualifiers MUST 4867 -- augment the following definition for PolicyQualifierId 4869 PolicyQualifierId ::= 4870 OBJECT IDENTIFIER ( id-qt-cps | id-qt-unotice ) 4872 -- CPS pointer qualifier 4874 CPSuri ::= IA5String 4875 -- user notice qualifier 4877 UserNotice ::= SEQUENCE { 4878 noticeRef NoticeReference OPTIONAL, 4879 explicitText DisplayText OPTIONAL} 4881 NoticeReference ::= SEQUENCE { 4882 organization DisplayText, 4883 noticeNumbers SEQUENCE OF INTEGER } 4885 DisplayText ::= CHOICE { 4886 ia5String IA5String (SIZE (1..200)), 4887 visibleString VisibleString (SIZE (1..200)), 4888 bmpString BMPString (SIZE (1..200)), 4889 utf8String UTF8String (SIZE (1..200)) } 4891 -- policy mapping extension OID and syntax 4893 id-ce-policyMappings OBJECT IDENTIFIER ::= { id-ce 33 } 4895 PolicyMappings ::= SEQUENCE SIZE (1..MAX) OF SEQUENCE { 4896 issuerDomainPolicy CertPolicyId, 4897 subjectDomainPolicy CertPolicyId } 4899 -- subject alternative name extension OID and syntax 4901 id-ce-subjectAltName OBJECT IDENTIFIER ::= { id-ce 17 } 4903 SubjectAltName ::= GeneralNames 4905 GeneralNames ::= SEQUENCE SIZE (1..MAX) OF GeneralName 4907 GeneralName ::= CHOICE { 4908 otherName [0] AnotherName, 4909 rfc822Name [1] IA5String, 4910 dNSName [2] IA5String, 4911 x400Address [3] ORAddress, 4912 directoryName [4] Name, 4913 ediPartyName [5] EDIPartyName, 4914 uniformResourceIdentifier [6] IA5String, 4915 iPAddress [7] OCTET STRING, 4916 registeredID [8] OBJECT IDENTIFIER } 4918 -- AnotherName replaces OTHER-NAME ::= TYPE-IDENTIFIER, as 4919 -- TYPE-IDENTIFIER is not supported in the '88 ASN.1 syntax 4921 AnotherName ::= SEQUENCE { 4922 type-id OBJECT IDENTIFIER, 4923 value [0] EXPLICIT ANY DEFINED BY type-id } 4925 EDIPartyName ::= SEQUENCE { 4926 nameAssigner [0] DirectoryString OPTIONAL, 4927 partyName [1] DirectoryString } 4929 -- issuer alternative name extension OID and syntax 4931 id-ce-issuerAltName OBJECT IDENTIFIER ::= { id-ce 18 } 4933 IssuerAltName ::= GeneralNames 4935 id-ce-subjectDirectoryAttributes OBJECT IDENTIFIER ::= { id-ce 9 } 4937 SubjectDirectoryAttributes ::= SEQUENCE SIZE (1..MAX) OF Attribute 4939 -- basic constraints extension OID and syntax 4941 id-ce-basicConstraints OBJECT IDENTIFIER ::= { id-ce 19 } 4943 BasicConstraints ::= SEQUENCE { 4944 cA BOOLEAN DEFAULT FALSE, 4945 pathLenConstraint INTEGER (0..MAX) OPTIONAL } 4947 -- name constraints extension OID and syntax 4949 id-ce-nameConstraints OBJECT IDENTIFIER ::= { id-ce 30 } 4951 NameConstraints ::= SEQUENCE { 4952 permittedSubtrees [0] GeneralSubtrees OPTIONAL, 4953 excludedSubtrees [1] GeneralSubtrees OPTIONAL } 4955 GeneralSubtrees ::= SEQUENCE SIZE (1..MAX) OF GeneralSubtree 4957 GeneralSubtree ::= SEQUENCE { 4958 base GeneralName, 4959 minimum [0] BaseDistance DEFAULT 0, 4960 maximum [1] BaseDistance OPTIONAL } 4962 BaseDistance ::= INTEGER (0..MAX) 4964 -- policy constraints extension OID and syntax 4966 id-ce-policyConstraints OBJECT IDENTIFIER ::= { id-ce 36 } 4968 PolicyConstraints ::= SEQUENCE { 4969 requireExplicitPolicy [0] SkipCerts OPTIONAL, 4970 inhibitPolicyMapping [1] SkipCerts OPTIONAL } 4972 SkipCerts ::= INTEGER (0..MAX) 4974 -- CRL distribution points extension OID and syntax 4976 id-ce-cRLDistributionPoints OBJECT IDENTIFIER ::= {id-ce 31} 4978 CRLDistributionPoints ::= SEQUENCE SIZE (1..MAX) OF DistributionPoint 4980 DistributionPoint ::= SEQUENCE { 4981 distributionPoint [0] DistributionPointName OPTIONAL, 4982 reasons [1] ReasonFlags OPTIONAL, 4983 cRLIssuer [2] GeneralNames OPTIONAL } 4985 DistributionPointName ::= CHOICE { 4986 fullName [0] GeneralNames, 4987 nameRelativeToCRLIssuer [1] RelativeDistinguishedName } 4989 ReasonFlags ::= BIT STRING { 4990 unused (0), 4991 keyCompromise (1), 4992 cACompromise (2), 4993 affiliationChanged (3), 4994 superseded (4), 4995 cessationOfOperation (5), 4996 certificateHold (6), 4997 privilegeWithdrawn (7), 4998 aACompromise (8) } 5000 -- extended key usage extension OID and syntax 5002 id-ce-extKeyUsage OBJECT IDENTIFIER ::= {id-ce 37} 5004 ExtKeyUsageSyntax ::= SEQUENCE SIZE (1..MAX) OF KeyPurposeId 5006 KeyPurposeId ::= OBJECT IDENTIFIER 5008 -- extended key purpose OIDs 5009 id-kp-serverAuth OBJECT IDENTIFIER ::= { id-kp 1 } 5010 id-kp-clientAuth OBJECT IDENTIFIER ::= { id-kp 2 } 5011 id-kp-codeSigning OBJECT IDENTIFIER ::= { id-kp 3 } 5012 id-kp-emailProtection OBJECT IDENTIFIER ::= { id-kp 4 } 5013 id-kp-timeStamping OBJECT IDENTIFIER ::= { id-kp 8 } 5014 id-kp-OCSPSigning OBJECT IDENTIFIER ::= { id-kp 9 } 5016 -- inhibit any policy OID and syntax 5018 id-ce-inhibitAnyPolicy OBJECT IDENTIFIER ::= { id-ce 54 } 5019 InhibitAnyPolicy ::= SkipCerts 5021 -- freshest (delta)CRL extension OID and syntax 5023 id-ce-freshestCRL OBJECT IDENTIFIER ::= { id-ce 46 } 5025 FreshestCRL ::= CRLDistributionPoints 5027 -- authority info access 5029 id-pe-authorityInfoAccess OBJECT IDENTIFIER ::= { id-pe 1 } 5031 AuthorityInfoAccessSyntax ::= 5032 SEQUENCE SIZE (1..MAX) OF AccessDescription 5034 AccessDescription ::= SEQUENCE { 5035 accessMethod OBJECT IDENTIFIER, 5036 accessLocation GeneralName } 5038 -- CRL number extension OID and syntax 5040 id-ce-cRLNumber OBJECT IDENTIFIER ::= { id-ce 20 } 5042 CRLNumber ::= INTEGER (0..MAX) 5044 -- issuing distribution point extension OID and syntax 5046 id-ce-issuingDistributionPoint OBJECT IDENTIFIER ::= { id-ce 28 } 5048 IssuingDistributionPoint ::= SEQUENCE { 5049 distributionPoint [0] DistributionPointName OPTIONAL, 5050 onlyContainsUserCerts [1] BOOLEAN DEFAULT FALSE, 5051 onlyContainsCACerts [2] BOOLEAN DEFAULT FALSE, 5052 onlySomeReasons [3] ReasonFlags OPTIONAL, 5053 indirectCRL [4] BOOLEAN DEFAULT FALSE, 5054 onlyContainsAttributeCerts [5] BOOLEAN DEFAULT FALSE } 5056 id-ce-deltaCRLIndicator OBJECT IDENTIFIER ::= { id-ce 27 } 5058 BaseCRLNumber ::= CRLNumber 5060 -- CRL reasons extension OID and syntax 5062 id-ce-cRLReasons OBJECT IDENTIFIER ::= { id-ce 21 } 5064 CRLReason ::= ENUMERATED { 5065 unspecified (0), 5066 keyCompromise (1), 5067 cACompromise (2), 5068 affiliationChanged (3), 5069 superseded (4), 5070 cessationOfOperation (5), 5071 certificateHold (6), 5072 removeFromCRL (8), 5073 privilegeWithdrawn (9), 5074 aACompromise (10) } 5076 -- certificate issuer CRL entry extension OID and syntax 5078 id-ce-certificateIssuer OBJECT IDENTIFIER ::= { id-ce 29 } 5080 CertificateIssuer ::= GeneralNames 5082 -- hold instruction extension OID and syntax 5084 id-ce-holdInstructionCode OBJECT IDENTIFIER ::= { id-ce 23 } 5086 HoldInstructionCode ::= OBJECT IDENTIFIER 5088 -- ANSI x9 holdinstructions 5090 -- ANSI x9 arc holdinstruction arc 5091 holdInstruction OBJECT IDENTIFIER ::= 5092 {joint-iso-itu-t(2) member-body(2) us(840) x9cm(10040) 2} 5094 -- ANSI X9 holdinstructions referenced by this standard 5095 id-holdinstruction-none OBJECT IDENTIFIER ::= 5096 {holdInstruction 1} -- deprecated 5097 id-holdinstruction-callissuer OBJECT IDENTIFIER ::= 5098 {holdInstruction 2} 5099 id-holdinstruction-reject OBJECT IDENTIFIER ::= 5100 {holdInstruction 3} 5102 -- invalidity date CRL entry extension OID and syntax 5104 id-ce-invalidityDate OBJECT IDENTIFIER ::= { id-ce 24 } 5106 InvalidityDate ::= GeneralizedTime 5108 END 5109 Appendix B. ASN.1 Notes 5111 CAs MUST force the serialNumber to be a non-negative integer, that 5112 is, the sign bit in the DER encoding of the INTEGER value MUST be 5113 zero - this can be done by adding a leading (leftmost) `00'H octet if 5114 necessary. This removes a potential ambiguity in mapping between a 5115 string of octets and an integer value. 5117 As noted in section 4.1.2.2, serial numbers can be expected to 5118 contain long integers. Certificate users MUST be able to handle 5119 serialNumber values up to 20 octets in length. Conformant CAs MUST 5120 NOT use serialNumber values longer than 20 octets. 5122 The construct "SEQUENCE SIZE (1..MAX) OF" appears in several ASN.1 5123 constructs. A valid ASN.1 sequence will have zero or more entries. 5124 The SIZE (1..MAX) construct constrains the sequence to have at least 5125 one entry. MAX indicates the upper bound is unspecified. 5126 Implementations are free to choose an upper bound that suits their 5127 environment. 5129 The construct "positiveInt ::= INTEGER (0..MAX)" defines positiveInt 5130 as a subtype of INTEGER containing integers greater than or equal to 5131 zero. The upper bound is unspecified. Implementations are free to 5132 select an upper bound that suits their environment. 5134 The character string type PrintableString supports a very basic Latin 5135 character set: the lower case letters 'a' through 'z', upper case 5136 letters 'A' through 'Z', the digits '0' through '9', eleven special 5137 characters ' = ( ) + , - . / : ? and space. 5139 Implementers should note that the at sign ('@') and underscore ('_') 5140 characters are not supported by the ASN.1 type PrintableString. 5141 These characters often appear in internet addresses. Such addresses 5142 MUST be encoded using an ASN.1 type that supports them. They are 5143 usually encoded as IA5String in either the emailAddress attribute 5144 within a distinguished name or the rfc822Name field of GeneralName. 5145 Conforming implementations MUST NOT encode strings which include 5146 either the at sign or underscore character as PrintableString. 5148 The character string type TeletexString is a superset of 5149 PrintableString. TeletexString supports a fairly standard (ASCII- 5150 like) Latin character set, Latin characters with non-spacing accents 5151 and Japanese characters. 5153 Named bit lists are BIT STRINGs where the values have been assigned 5154 names. This specification makes use of named bit lists in the 5155 definitions for the key usage extension and CRL reasons field in the 5156 CRL distribution points and freshest CRL certificate extensions, and 5157 the issuing distribution point CRL extension. When DER encoding a 5158 named bit list, trailing zeroes MUST be omitted. That is, the 5159 encoded value ends with the last named bit that is set to one. 5161 The character string type UniversalString supports any of the 5162 characters allowed by ISO 10646-1 [ISO 10646]. ISO 10646-1 is the 5163 Universal multiple-octet coded Character Set (UCS). ISO 10646-1 5164 specifies the architecture and the "basic multilingual plane" - a 5165 large standard character set which includes all major world character 5166 standards. 5168 The character string type UTF8String was introduced in the 1997 5169 version of ASN.1, and UTF8String was added to the list of choices for 5170 DirectoryString in the 2001 version of X.520 [X.520]. UTF8String is 5171 a universal type and has been assigned tag number 12. The content of 5172 UTF8String was defined by RFC 2044 [RFC 2044] and updated in RFC 2279 5173 [RFC 2279]. 5175 In anticipation of these changes, and in conformance with IETF Best 5176 Practices codified in RFC 2277 [RFC 2277], IETF Policy on Character 5177 Sets and Languages, this document includes UTF8String as a choice in 5178 DirectoryString and the CPS qualifier extensions. 5180 Implementers should note that the DER encoding of the SET OF values 5181 requires ordering of the encodings of the values. In particular, 5182 this issue arises with respect to distinguished names. 5184 Implementers should note that the DER encoding of SET or SEQUENCE 5185 components whose value is the DEFAULT omit the component from the 5186 encoded certificate or CRL. For example, a BasicConstraints 5187 extension whose cA value is FALSE would omit the cA boolean from the 5188 encoded certificate. 5190 Object Identifiers (OIDs) are used throughout this specification to 5191 identify certificate policies, public key and signature algorithms, 5192 certificate extensions, etc. There is no maximum size for OIDs. 5193 This specification mandates support for OIDs which have arc elements 5194 with values that are less than 2^28, that is, they MUST be between 0 5195 and 268,435,455, inclusive. This allows each arc element to be 5196 represented within a single 32 bit word. Implementations MUST also 5197 support OIDs where the length of the dotted decimal (see [RFC 2252], 5198 section 4.1) string representation can be up to 100 bytes 5199 (inclusive). Implementations MUST be able to handle OIDs with up to 5200 20 elements (inclusive). CAs SHOULD NOT issue certificates which 5201 contain OIDs that exceed these requirements. 5203 Implementors are warned that the X.500 standards community has 5204 developed a series of extensibility rules. These rules determine 5205 when an ASN.1 definition can be changed without assigning a new 5206 object identifier (OID). For example, at least two extension 5207 definitions included in RFC 2459 [RFC 2459], the predecessor to this 5208 profile document, have different ASN.1 definitions in this 5209 specification, but the same OID is used. If unknown elements appear 5210 within an extension, and the extension is not marked critical, those 5211 unknown elements ought to be ignored, as follows: 5213 (a) ignore all unknown bit name assignments within a bit string; 5215 (b) ignore all unknown named numbers in an ENUMERATED type or 5216 INTEGER type that is being used in the enumerated style, provided 5217 the number occurs as an optional element of a SET or SEQUENCE; and 5219 (c) ignore all unknown elements in SETs, at the end of SEQUENCEs, 5220 or in CHOICEs where the CHOICE is itself an optional element of a 5221 SET or SEQUENCE. 5223 If an extension containing unexpected values is marked critical, the 5224 implementation MUST reject the certificate or CRL containing the 5225 unrecognized extension. 5227 Appendix C. Examples 5229 This section contains four examples: three certificates and a CRL. 5230 The first two certificates and the CRL comprise a minimal 5231 certification path. 5233 Section C.1 contains an annotated hex dump of a "self-signed" 5234 certificate issued by a CA whose distinguished name is 5235 cn=us,o=gov,ou=nist. The certificate contains a DSA public key with 5236 parameters, and is signed by the corresponding DSA private key. 5238 Section C.2 contains an annotated hex dump of an end entity 5239 certificate. The end entity certificate contains a DSA public key, 5240 and is signed by the private key corresponding to the "self-signed" 5241 certificate in section C.1. 5243 Section C.3 contains a dump of an end entity certificate which 5244 contains an RSA public key and is signed with RSA and MD5. This 5245 certificate is not part of the minimal certification path. 5247 Section C.4 contains an annotated hex dump of a CRL. The CRL is 5248 issued by the CA whose distinguished name is cn=us,o=gov,ou=nist and 5249 the list of revoked certificates includes the end entity certificate 5250 presented in C.2. 5252 The certificates were processed using Peter Gutman's dumpasn1 utility 5253 to generate the output. The source for the dumpasn1 utility is 5254 available at . The 5255 binaries for the certificates and CRLs are available at 5256 . 5258 C.1 Certificate 5260 This section contains an annotated hex dump of a 699 byte version 3 5261 certificate. The certificate contains the following information: 5262 (a) the serial number is 23 (17 hex); 5263 (b) the certificate is signed with DSA and the SHA-1 hash algorithm; 5264 (c) the issuer's distinguished name is OU=NIST; O=gov; C=US 5265 (d) and the subject's distinguished name is OU=NIST; O=gov; C=US 5266 (e) the certificate was issued on June 30, 1997 and will expire on 5267 December 31, 1997; 5268 (f) the certificate contains a 1024 bit DSA public key with 5269 parameters; 5270 (g) the certificate contains a subject key identifier extension 5271 generated using method (1) of section 4.2.1.2; and 5272 (h) the certificate is a CA certificate (as indicated through the 5273 basic constraints extension.) 5275 0 30 699: SEQUENCE { 5276 4 30 635: SEQUENCE { 5277 8 A0 3: [0] { 5278 10 02 1: INTEGER 2 5279 : } 5280 13 02 1: INTEGER 17 5281 16 30 9: SEQUENCE { 5282 18 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5283 : } 5284 27 30 42: SEQUENCE { 5285 29 31 11: SET { 5286 31 30 9: SEQUENCE { 5287 33 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5288 38 13 2: PrintableString 'US' 5289 : } 5290 : } 5291 42 31 12: SET { 5292 44 30 10: SEQUENCE { 5293 46 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5294 51 13 3: PrintableString 'gov' 5295 : } 5296 : } 5297 56 31 13: SET { 5298 58 30 11: SEQUENCE { 5299 60 06 3: OBJECT IDENTIFIER 5300 : organizationalUnitName (2 5 4 11) 5302 65 13 4: PrintableString 'NIST' 5303 : } 5304 : } 5305 : } 5306 71 30 30: SEQUENCE { 5307 73 17 13: UTCTime '970630000000Z' 5308 88 17 13: UTCTime '971231000000Z' 5309 : } 5310 103 30 42: SEQUENCE { 5311 105 31 11: SET { 5312 107 30 9: SEQUENCE { 5313 109 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5314 114 13 2: PrintableString 'US' 5315 : } 5316 : } 5317 118 31 12: SET { 5318 120 30 10: SEQUENCE { 5319 122 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5320 127 13 3: PrintableString 'gov' 5321 : } 5322 : } 5323 132 31 13: SET { 5324 134 30 11: SEQUENCE { 5325 136 06 3: OBJECT IDENTIFIER 5326 : organizationalUnitName (2 5 4 11) 5327 141 13 4: PrintableString 'NIST' 5328 : } 5329 : } 5330 : } 5331 147 30 440: SEQUENCE { 5332 151 30 300: SEQUENCE { 5333 155 06 7: OBJECT IDENTIFIER dsa (1 2 840 10040 4 1) 5334 164 30 287: SEQUENCE { 5335 168 02 129: INTEGER 5336 : 00 B6 8B 0F 94 2B 9A CE A5 25 C6 F2 ED FC 5337 : FB 95 32 AC 01 12 33 B9 E0 1C AD 90 9B BC 5338 : 48 54 9E F3 94 77 3C 2C 71 35 55 E6 FE 4F 5339 : 22 CB D5 D8 3E 89 93 33 4D FC BD 4F 41 64 5340 : 3E A2 98 70 EC 31 B4 50 DE EB F1 98 28 0A 5341 : C9 3E 44 B3 FD 22 97 96 83 D0 18 A3 E3 BD 5342 : 35 5B FF EE A3 21 72 6A 7B 96 DA B9 3F 1E 5343 : 5A 90 AF 24 D6 20 F0 0D 21 A7 D4 02 B9 1A 5344 : FC AC 21 FB 9E 94 9E 4B 42 45 9E 6A B2 48 5345 : 63 FE 43 5346 300 02 21: INTEGER 5347 : 00 B2 0D B0 B1 01 DF 0C 66 24 FC 13 92 BA 5348 : 55 F7 7D 57 74 81 E5 5349 323 02 129: INTEGER 5350 : 00 9A BF 46 B1 F5 3F 44 3D C9 A5 65 FB 91 5351 : C0 8E 47 F1 0A C3 01 47 C2 44 42 36 A9 92 5352 : 81 DE 57 C5 E0 68 86 58 00 7B 1F F9 9B 77 5353 : A1 C5 10 A5 80 91 78 51 51 3C F6 FC FC CC 5354 : 46 C6 81 78 92 84 3D F4 93 3D 0C 38 7E 1A 5355 : 5B 99 4E AB 14 64 F6 0C 21 22 4E 28 08 9C 5356 : 92 B9 66 9F 40 E8 95 F6 D5 31 2A EF 39 A2 5357 : 62 C7 B2 6D 9E 58 C4 3A A8 11 81 84 6D AF 5358 : F8 B4 19 B4 C2 11 AE D0 22 3B AA 20 7F EE 5359 : 1E 57 18 5360 : } 5361 : } 5362 455 03 133: BIT STRING 0 unused bits, encapsulates { 5363 459 02 129: INTEGER 5364 : 00 B5 9E 1F 49 04 47 D1 DB F5 3A DD CA 04 5365 : 75 E8 DD 75 F6 9B 8A B1 97 D6 59 69 82 D3 5366 : 03 4D FD 3B 36 5F 4A F2 D1 4E C1 07 F5 D1 5367 : 2A D3 78 77 63 56 EA 96 61 4D 42 0B 7A 1D 5368 : FB AB 91 A4 CE DE EF 77 C8 E5 EF 20 AE A6 5369 : 28 48 AF BE 69 C3 6A A5 30 F2 C2 B9 D9 82 5370 : 2B 7D D9 C4 84 1F DE 0D E8 54 D7 1B 99 2E 5371 : B3 D0 88 F6 D6 63 9B A7 E2 0E 82 D4 3B 8A 5372 : 68 1B 06 56 31 59 0B 49 EB 99 A5 D5 81 41 5373 : 7B C9 55 5374 : } 5375 : } 5376 591 A3 50: [3] { 5377 593 30 48: SEQUENCE { 5378 595 30 29: SEQUENCE { 5379 597 06 3: OBJECT IDENTIFIER 5380 : subjectKeyIdentifier (2 5 29 14) 5381 602 04 22: OCTET STRING, encapsulates { 5382 604 04 20: OCTET STRING 5383 : 86 CA A5 22 81 62 EF AD 0A 89 BC AD 72 41 5384 : 2C 29 49 F4 86 56 5385 : } 5386 : } 5387 626 30 15: SEQUENCE { 5388 628 06 3: OBJECT IDENTIFIER basicConstraints (2 5 29 19) 5389 633 01 1: BOOLEAN TRUE 5390 636 04 5: OCTET STRING, encapsulates { 5391 638 30 3: SEQUENCE { 5392 640 01 1: BOOLEAN TRUE 5393 : } 5394 : } 5395 : } 5396 : } 5397 : } 5398 : } 5399 643 30 9: SEQUENCE { 5400 645 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5401 : } 5402 654 03 47: BIT STRING 0 unused bits, encapsulates { 5403 657 30 44: SEQUENCE { 5404 659 02 20: INTEGER 5405 : 43 1B CF 29 25 45 C0 4E 52 E7 7D D6 FC B1 5406 : 66 4C 83 CF 2D 77 5407 681 02 20: INTEGER 5408 : 0B 5B 9A 24 11 98 E8 F3 86 90 04 F6 08 A9 5409 : E1 8D A5 CC 3A D4 5410 : } 5411 : } 5412 : } 5414 C.2 Certificate 5416 This section contains an annotated hex dump of a 730 byte version 3 5417 certificate. The certificate contains the following information: 5418 (a the serial number is 18 (12 hex); 5419 (b) the certificate is signed with DSA and the SHA-1 hash algorithm; 5420 (c) the issuer's distinguished name is OU=nist; O=gov; C=US 5421 (d) and the subject's distinguished name is CN=Tim Polk; OU=nist; 5422 O=gov; C=US 5423 (e) the certificate was valid from July 30, 1997 through December 1, 5424 1997; 5425 (f) the certificate contains a 1024 bit DSA public key; 5426 (g) the certificate is an end entity certificate, as the basic 5427 constraints extension is not present; 5428 (h) the certificate contains an authority key identifier extension 5429 matching the subject key identifier of the certificate in Appendix 5430 C.1; and 5431 (i) the certificate includes one alternative name - an RFC 822 5432 address of "wpolk@nist.gov". 5434 0 30 730: SEQUENCE { 5435 4 30 665: SEQUENCE { 5436 8 A0 3: [0] { 5437 10 02 1: INTEGER 2 5438 : } 5439 13 02 1: INTEGER 18 5440 16 30 9: SEQUENCE { 5441 18 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5442 : } 5443 27 30 42: SEQUENCE { 5444 29 31 11: SET { 5445 31 30 9: SEQUENCE { 5446 33 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5447 38 13 2: PrintableString 'US' 5448 : } 5449 : } 5450 42 31 12: SET { 5451 44 30 10: SEQUENCE { 5452 46 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5453 51 13 3: PrintableString 'gov' 5454 : } 5455 : } 5456 56 31 13: SET { 5457 58 30 11: SEQUENCE { 5458 60 06 3: OBJECT IDENTIFIER 5459 : organizationalUnitName (2 5 4 11) 5460 65 13 4: PrintableString 'NIST' 5461 : } 5462 : } 5463 : } 5464 71 30 30: SEQUENCE { 5465 73 17 13: UTCTime '970730000000Z' 5466 88 17 13: UTCTime '971201000000Z' 5467 : } 5468 103 30 61: SEQUENCE { 5469 105 31 11: SET { 5470 107 30 9: SEQUENCE { 5471 109 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5472 114 13 2: PrintableString 'US' 5473 : } 5474 : } 5475 118 31 12: SET { 5476 120 30 10: SEQUENCE { 5477 122 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5478 127 13 3: PrintableString 'gov' 5479 : } 5480 : } 5481 132 31 13: SET { 5482 134 30 11: SEQUENCE { 5483 136 06 3: OBJECT IDENTIFIER 5484 : organizationalUnitName (2 5 4 11) 5485 141 13 4: PrintableString 'NIST' 5486 : } 5487 : } 5488 147 31 17: SET { 5489 149 30 15: SEQUENCE { 5490 151 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 5491 156 13 8: PrintableString 'Tim Polk' 5492 : } 5493 : } 5494 : } 5495 166 30 439: SEQUENCE { 5496 170 30 300: SEQUENCE { 5497 174 06 7: OBJECT IDENTIFIER dsa (1 2 840 10040 4 1) 5498 183 30 287: SEQUENCE { 5499 187 02 129: INTEGER 5500 : 00 B6 8B 0F 94 2B 9A CE A5 25 C6 F2 ED FC 5501 : FB 95 32 AC 01 12 33 B9 E0 1C AD 90 9B BC 5502 : 48 54 9E F3 94 77 3C 2C 71 35 55 E6 FE 4F 5503 : 22 CB D5 D8 3E 89 93 33 4D FC BD 4F 41 64 5504 : 3E A2 98 70 EC 31 B4 50 DE EB F1 98 28 0A 5505 : C9 3E 44 B3 FD 22 97 96 83 D0 18 A3 E3 BD 5506 : 35 5B FF EE A3 21 72 6A 7B 96 DA B9 3F 1E 5507 : 5A 90 AF 24 D6 20 F0 0D 21 A7 D4 02 B9 1A 5508 : FC AC 21 FB 9E 94 9E 4B 42 45 9E 6A B2 48 5509 : 63 FE 43 5510 319 02 21: INTEGER 5511 : 00 B2 0D B0 B1 01 DF 0C 66 24 FC 13 92 BA 5512 : 55 F7 7D 57 74 81 E5 5513 342 02 129: INTEGER 5514 : 00 9A BF 46 B1 F5 3F 44 3D C9 A5 65 FB 91 5515 : C0 8E 47 F1 0A C3 01 47 C2 44 42 36 A9 92 5516 : 81 DE 57 C5 E0 68 86 58 00 7B 1F F9 9B 77 5517 : A1 C5 10 A5 80 91 78 51 51 3C F6 FC FC CC 5518 : 46 C6 81 78 92 84 3D F4 93 3D 0C 38 7E 1A 5519 : 5B 99 4E AB 14 64 F6 0C 21 22 4E 28 08 9C 5520 : 92 B9 66 9F 40 E8 95 F6 D5 31 2A EF 39 A2 5521 : 62 C7 B2 6D 9E 58 C4 3A A8 11 81 84 6D AF 5522 : F8 B4 19 B4 C2 11 AE D0 22 3B AA 20 7F EE 5523 : 1E 57 18 5524 : } 5525 : } 5526 474 03 132: BIT STRING 0 unused bits, encapsulates { 5527 478 02 128: INTEGER 5528 : 30 B6 75 F7 7C 20 31 AE 38 BB 7E 0D 2B AB 5529 : A0 9C 4B DF 20 D5 24 13 3C CD 98 E5 5F 6C 5530 : B7 C1 BA 4A BA A9 95 80 53 F0 0D 72 DC 33 5531 : 37 F4 01 0B F5 04 1F 9D 2E 1F 62 D8 84 3A 5532 : 9B 25 09 5A 2D C8 46 8E 2B D4 F5 0D 3B C7 5533 : 2D C6 6C B9 98 C1 25 3A 44 4E 8E CA 95 61 5534 : 35 7C CE 15 31 5C 23 13 1E A2 05 D1 7A 24 5535 : 1C CB D3 72 09 90 FF 9B 9D 28 C0 A1 0A EC 5536 : 46 9F 0D B8 D0 DC D0 18 A6 2B 5E F9 8F B5 5537 : 95 BE 5538 : } 5539 : } 5540 609 A3 62: [3] { 5541 611 30 60: SEQUENCE { 5542 613 30 25: SEQUENCE { 5543 615 06 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) 5544 620 04 18: OCTET STRING, encapsulates { 5545 622 30 16: SEQUENCE { 5546 624 81 14: [1] 'wpolk@nist.gov' 5547 : } 5548 : } 5549 : } 5550 640 30 31: SEQUENCE { 5551 642 06 3: OBJECT IDENTIFIER 5552 : authorityKeyIdentifier (2 5 29 35) 5553 647 04 24: OCTET STRING, encapsulates { 5554 649 30 22: SEQUENCE { 5555 651 80 20: [0] 5556 : 86 CA A5 22 81 62 EF AD 0A 89 BC AD 72 5557 : 41 2C 29 49 F4 86 56 5558 : } 5559 : } 5560 : } 5561 : } 5562 : } 5563 : } 5564 673 30 9: SEQUENCE { 5565 675 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5566 : } 5567 684 03 48: BIT STRING 0 unused bits, encapsulates { 5568 687 30 45: SEQUENCE { 5569 689 02 20: INTEGER 5570 : 36 97 CB E3 B4 2C E1 BB 61 A9 D3 CC 24 CC 5571 : 22 92 9F F4 F5 87 5572 711 02 21: INTEGER 5573 : 00 AB C9 79 AF D2 16 1C A9 E3 68 A9 14 10 5574 : B4 A0 2E FF 22 5A 73 5575 : } 5576 : } 5577 : } 5579 C.3 End Entity Certificate Using RSA 5581 This section contains an annotated hex dump of a 654 byte version 3 5582 certificate. The certificate contains the following information: 5583 (a) the serial number is 256; 5584 (b) the certificate is signed with RSA and the SHA-1 hash algorithm; 5585 (c) the issuer's distinguished name is OU=NIST; O=gov; C=US 5586 (d) and the subject's distinguished name is CN=Tim Polk; OU=NIST; 5587 O=gov; C=US 5588 (e) the certificate was issued on May 21, 1996 at 09:58:26 and 5589 expired on May 21, 1997 at 09:58:26; 5590 (f) the certificate contains a 1024 bit RSA public key; 5591 (g) the certificate is an end entity certificate (not a CA 5592 certificate); 5593 (h) the certificate includes an alternative subject name of 5594 "" and an 5595 alternative issuer name of "" - both are URLs; 5596 (i) the certificate include an authority key identifier extension 5597 and a certificate policies extension psecifying the policy OID 5598 2.16.840.1.101.3.2.1.48.9; and 5599 (j) the certificate includes a critical key usage extension 5600 specifying that the public key is intended for verification of 5601 digital signatures. 5603 0 30 654: SEQUENCE { 5604 4 30 503: SEQUENCE { 5605 8 A0 3: [0] { 5606 10 02 1: INTEGER 2 5607 : } 5608 13 02 2: INTEGER 256 5609 17 30 13: SEQUENCE { 5610 19 06 9: OBJECT IDENTIFIER 5611 : sha1withRSAEncryption (1 2 840 113549 1 1 5) 5612 30 05 0: NULL 5613 : } 5614 32 30 42: SEQUENCE { 5615 34 31 11: SET { 5616 36 30 9: SEQUENCE { 5617 38 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5618 43 13 2: PrintableString 'US' 5619 : } 5620 : } 5621 47 31 12: SET { 5622 49 30 10: SEQUENCE { 5623 51 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5624 56 13 3: PrintableString 'gov' 5625 : } 5626 : } 5627 61 31 13: SET { 5628 63 30 11: SEQUENCE { 5629 65 06 3: OBJECT IDENTIFIER 5630 : organizationalUnitName (2 5 4 11) 5631 70 13 4: PrintableString 'NIST' 5632 : } 5633 : } 5634 : } 5635 76 30 30: SEQUENCE { 5636 78 17 13: UTCTime '960521095826Z' 5637 93 17 13: UTCTime '970521095826Z' 5638 : } 5639 108 30 61: SEQUENCE { 5640 110 31 11: SET { 5641 112 30 9: SEQUENCE { 5642 114 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5643 119 13 2: PrintableString 'US' 5644 : } 5645 : } 5646 123 31 12: SET { 5647 125 30 10: SEQUENCE { 5648 127 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5649 132 13 3: PrintableString 'gov' 5650 : } 5651 : } 5652 137 31 13: SET { 5653 139 30 11: SEQUENCE { 5654 141 06 3: OBJECT IDENTIFIER 5655 : organizationalUnitName (2 5 4 11) 5656 146 13 4: PrintableString 'NIST' 5657 : } 5658 : } 5659 152 31 17: SET { 5660 154 30 15: SEQUENCE { 5661 156 06 3: OBJECT IDENTIFIER commonName (2 5 4 3) 5662 161 13 8: PrintableString 'Tim Polk' 5663 : } 5664 : } 5665 : } 5666 171 30 159: SEQUENCE { 5667 174 30 13: SEQUENCE { 5668 176 06 9: OBJECT IDENTIFIER 5669 : rsaEncryption (1 2 840 113549 1 1 1) 5670 187 05 0: NULL 5671 : } 5672 189 03 141: BIT STRING 0 unused bits, encapsulates { 5673 193 30 137: SEQUENCE { 5674 196 02 129: INTEGER 5675 : 00 E1 6A E4 03 30 97 02 3C F4 10 F3 B5 1E 5676 : 4D 7F 14 7B F6 F5 D0 78 E9 A4 8A F0 A3 75 5677 : EC ED B6 56 96 7F 88 99 85 9A F2 3E 68 77 5678 : 87 EB 9E D1 9F C0 B4 17 DC AB 89 23 A4 1D 5679 : 7E 16 23 4C 4F A8 4D F5 31 B8 7C AA E3 1A 5680 : 49 09 F4 4B 26 DB 27 67 30 82 12 01 4A E9 5681 : 1A B6 C1 0C 53 8B 6C FC 2F 7A 43 EC 33 36 5682 : 7E 32 B2 7B D5 AA CF 01 14 C6 12 EC 13 F2 5683 : 2D 14 7A 8B 21 58 14 13 4C 46 A3 9A F2 16 5684 : 95 FF 23 5685 328 02 3: INTEGER 65537 5686 : } 5687 : } 5688 : } 5689 333 A3 175: [3] { 5690 336 30 172: SEQUENCE { 5691 339 30 63: SEQUENCE { 5692 341 06 3: OBJECT IDENTIFIER subjectAltName (2 5 29 17) 5693 346 04 56: OCTET STRING, encapsulates { 5694 348 30 54: SEQUENCE { 5695 350 86 52: [6] 5696 : 'http://www.itl.nist.gov/div893/staff/' 5697 : 'polk/index.html' 5698 : } 5699 : } 5700 : } 5701 404 30 31: SEQUENCE { 5702 406 06 3: OBJECT IDENTIFIER issuerAltName (2 5 29 18) 5703 411 04 24: OCTET STRING, encapsulates { 5704 413 30 22: SEQUENCE { 5705 415 86 20: [6] 'http://www.nist.gov/' 5706 : } 5707 : } 5708 : } 5709 437 30 31: SEQUENCE { 5710 439 06 3: OBJECT IDENTIFIER 5711 : authorityKeyIdentifier (2 5 29 35) 5712 444 04 24: OCTET STRING, encapsulates { 5713 446 30 22: SEQUENCE { 5714 448 80 20: [0] 5715 : 08 68 AF 85 33 C8 39 4A 7A F8 82 93 8E 5716 : 70 6A 4A 20 84 2C 32 5717 : } 5718 : } 5719 : } 5720 470 30 23: SEQUENCE { 5721 472 06 3: OBJECT IDENTIFIER 5722 : certificatePolicies (2 5 29 32) 5723 477 04 16: OCTET STRING, encapsulates { 5724 479 30 14: SEQUENCE { 5725 481 30 12: SEQUENCE { 5726 483 06 10: OBJECT IDENTIFIER 5727 : '2 16 840 1 101 3 2 1 48 9' 5728 : } 5729 : } 5730 : } 5731 : } 5732 495 30 14: SEQUENCE { 5733 497 06 3: OBJECT IDENTIFIER keyUsage (2 5 29 15) 5734 502 01 1: BOOLEAN TRUE 5735 505 04 4: OCTET STRING, encapsulates { 5736 507 03 2: BIT STRING 7 unused bits 5737 : '1'B (bit 0) 5738 : } 5739 : } 5740 : } 5741 : } 5742 : } 5743 511 30 13: SEQUENCE { 5744 513 06 9: OBJECT IDENTIFIER 5745 : sha1withRSAEncryption (1 2 840 113549 1 1 5) 5746 524 05 0: NULL 5747 : } 5748 526 03 129: BIT STRING 0 unused bits 5749 : 1E 07 77 6E 66 B5 B6 B8 57 F0 03 DC 6F 77 5750 : 6D AF 55 1D 74 E5 CE 36 81 FC 4B C5 F4 47 5751 : 82 C4 0A 25 AA 8D D6 7D 3A 89 AB 44 34 39 5752 : F6 BD 61 1A 78 85 7A B8 1E 92 A2 22 2F CE 5753 : 07 1A 08 8E F1 46 03 59 36 4A CB 60 E6 03 5754 : 40 01 5B 2A 44 D6 E4 7F EB 43 5E 74 0A E6 5755 : E4 F9 3E E1 44 BE 1F E7 5F 5B 2C 41 8D 08 5756 : BD 26 FE 6A A6 C3 2F B2 3B 41 12 6B C1 06 5757 : 8A B8 4C 91 59 EB 2F 38 20 2A 67 74 20 0B 5758 : 77 F3 5759 : } 5761 C.4 Certificate Revocation List 5763 This section contains an annotated hex dump of a version 2 CRL with 5764 one extension (cRLNumber). The CRL was issued by OU=NIST; O=gov; C=US 5765 on August 7, 1997; the next scheduled issuance was September 7, 1997. 5766 The CRL includes one revoked certificates: serial number 18 (12 hex), 5767 which was revoked on July 31, 1997 due to keyCompromise. The CRL 5768 itself is number 18, and it was signed with DSA and SHA-1. 5770 0 30 203: SEQUENCE { 5771 3 30 140: SEQUENCE { 5772 6 02 1: INTEGER 1 5773 9 30 9: SEQUENCE { 5774 11 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5775 : } 5776 20 30 42: SEQUENCE { 5777 22 31 11: SET { 5778 24 30 9: SEQUENCE { 5779 26 06 3: OBJECT IDENTIFIER countryName (2 5 4 6) 5780 31 13 2: PrintableString 'US' 5781 : } 5782 : } 5783 35 31 12: SET { 5784 37 30 10: SEQUENCE { 5785 39 06 3: OBJECT IDENTIFIER organizationName (2 5 4 10) 5786 44 13 3: PrintableString 'gov' 5787 : } 5788 : } 5789 49 31 13: SET { 5790 51 30 11: SEQUENCE { 5791 53 06 3: OBJECT IDENTIFIER 5792 : organizationalUnitName (2 5 4 11) 5793 58 13 4: PrintableString 'NIST' 5794 : } 5795 : } 5796 : } 5797 64 17 13: UTCTime '970807000000Z' 5798 79 17 13: UTCTime '970907000000Z' 5799 94 30 34: SEQUENCE { 5800 96 30 32: SEQUENCE { 5801 98 02 1: INTEGER 18 5802 101 17 13: UTCTime '970731000000Z' 5803 116 30 12: SEQUENCE { 5804 118 30 10: SEQUENCE { 5805 120 06 3: OBJECT IDENTIFIER cRLReason (2 5 29 21) 5806 125 04 3: OCTET STRING, encapsulates { 5807 127 0A 1: ENUMERATED 1 5808 : } 5809 : } 5810 : } 5811 : } 5812 : } 5813 130 A0 14: [0] { 5814 132 30 12: SEQUENCE { 5815 134 30 10: SEQUENCE { 5816 136 06 3: OBJECT IDENTIFIER cRLNumber (2 5 29 20) 5817 141 04 3: OCTET STRING, encapsulates { 5818 143 02 1: INTEGER 12 5819 : } 5820 : } 5821 : } 5822 : } 5823 : } 5824 146 30 9: SEQUENCE { 5825 148 06 7: OBJECT IDENTIFIER dsaWithSha1 (1 2 840 10040 4 3) 5826 : } 5827 157 03 47: BIT STRING 0 unused bits, encapsulates { 5828 160 30 44: SEQUENCE { 5829 162 02 20: INTEGER 5830 : 22 4E 9F 43 BA 95 06 34 F2 BB 5E 65 DB A6 5831 : 80 05 C0 3A 29 47 5832 184 02 20: INTEGER 5833 : 59 1A 57 C9 82 D7 02 21 14 C3 D4 0B 32 1B 5834 : 96 16 B1 1F 46 5A 5835 : } 5836 : } 5837 : } 5839 Appendix D. Author Addresses: 5841 Russell Housley 5842 RSA Laboratories 5843 918 Spring Knoll Drive 5844 Herndon, VA 20170 5845 USA 5846 rhousley@rsasecurity.com 5848 Warwick Ford 5849 VeriSign, Inc. 5850 One Alewife Center 5851 Cambridge, MA 02140 5852 USA 5853 wford@verisign.com 5855 Tim Polk 5856 NIST 5857 Building 820, Room 426 5858 Gaithersburg, MD 20899 5859 USA 5860 wpolk@nist.gov 5862 David Solo 5863 Citigroup 5864 909 Third Ave, 16th Floor 5865 New York, NY 10043 5866 USA 5867 dsolo@alum.mit.edu 5869 Appendix E. Full Copyright Statement 5871 Copyright (C) The Internet Society (date). All Rights Reserved. 5873 This document and translations of it may be copied and furnished to 5874 others, and derivative works that comment on or otherwise explain it 5875 or assist in its implementation may be prepared, copied, published 5876 and distributed, in whole or in part, without restriction of any 5877 kind, provided that the above copyright notice and this paragraph are 5878 included on all such copies and derivative works. In addition, the 5879 ASN.1 modules presented in Appendix A may be used in whole or in part 5880 without inclusion of the copyright notice. However, this document 5881 itself may not be modified in any way, such as by removing the 5882 copyright notice or references to the Internet Society or other 5883 Internet organizations, except as needed for the purpose of 5884 developing Internet standards in which case the procedures for 5885 copyrights defined in the Internet Standards process shall be 5886 followed, or as required to translate it into languages other than 5887 English. 5889 The limited permissions granted above are perpetual and will not be 5890 revoked by the Internet Society or its successors or assigns. This 5891 document and the information contained herein is provided on an "AS 5892 IS" basis and THE INTERNET SOCIETY AND THE INTERNET ENGINEERING TASK 5893 FORCE DISCLAIMS ALL WARRANTIES, EXPRESS OR IMPLIED, INCLUDING BUT NOT 5894 LIMITED TO ANY WARRANTY THAT THE USE OF THE INFORMATION HEREIN WILL 5895 NOT INFRINGE ANY RIGHTS OR ANY IMPLIED WARRANTIES OF MERCHANTABILITY 5896 OR FITNESS FOR A PARTICULAR PURPOSE.